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Sun-Mar centrex 2000 af Owner's Manual

centrex 2000 af ac/dc\ centrex 2000 af ne

Made by: Sun-Mar
Type: Owner's Manual
Category: Plumbing Product
Pages: 18
Size: 0.53 MB


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Serial    #  ________________



March 2008
Rev D3

Product Info: (905) 332-1314          Fax: (905) 332-1315         Tech. Service: (888) 341-0782                

E-mail: compost@sun-mar.com                                                 http://www.sun-mar.com

600 Main St

5370 South Service Rd.

Tonawanda NY

Burlington, ON

14150-0888 USA



Weekend & Vacation Use
(Cottage Use)

NE Units; 5 Adults or families of 7 or
Electric Units; 6 Adults or families of 8 

Residential & Continuous Use

NE units; 3 Adults or a family of 5 or
Electric Units; 4 Adults or families of 6 

Standard 41

Certified for liquid containment,
odors, and solid end products in
both residential and cottage use

Certified to NSF/ANSI Standard 41




Electrical  Specifacations

2000                                    2000  NE                      2000  AC/DC

Maximum Amps

2.4                         NA


Fan Watts

35 req.

1.4 opt.

(Required or Optional                  

35 req./        


1.4 opt.

Heater Watts

370                        NA                    370

(When on) 

Average Power Use                  200                         NA                    200    
In Watts (Heater on         
1/2 time)    


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-  34  -


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-  33  -

-  2  -



Chapter  3

Chapter  4

Chapter  5



Chapter  1

Chapter  2

How your composting
toilet Works

How Composting Works
The Composting Chamber
Compost Finishing Drawer
Evaporation Chamber
Winter Use
CENTREX 2000 AF  Family Explosion
CENTREX 2000 AF  Family 
Part Numbers
Wiring Diagram
Dry Toilet Explosion Diagram


Check for Damage
Check for Parts and Functionality
Placement of AF Dry Toilet


Rough in Dimensions
AF Dry Toilet Rough In Dimensions
Included in Your Kit
Installing the AF Toilet Base
The Transition Piece
Determining if an Extention Pipe
Piece is Needed
Assembling Extension Pipe Pieces
Finishing the AF Toilet Installation
Adjusting the Air Intake
Installing optional Vent on  Toilet
Cutting Holes in the Toilet Chute
Drain Installation
Handling Effluent
Vent Piping Location 
Adjusting the Fan Gate
Vent Piping Installation
Leading the Vent Through the Roof
The Diffusor
Electrical Considerations
12 Volt Fan Installation










Start Up and Use

Initial System Start Up
Annual Start Up
Periodic Check Up
Ongoing Maintenance


Aerobic Compost Requirements
Compost Too Wet
Compost Too Dry
Waste not Breaking Down
Drum Too Full


Urine Odour In Washroom
Occasional Urine Odour Outside
Sewage Odour when drum turns
Fan Noisy
Fan Not Working
Liquid Buildup/
Lack of Evaporation
Overflowing Liquid
Heating System Not Working
Liquid In Finishing Drawer
Drum Will Not Stay Vertical
Drum Will Not Turn
Drum Door Not Opening/
Waste Not Exiting Waste Pipe

Warranty  Information

Basic Maintenance












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Composting is a natural recycling process where human
waste and toilet paper are broken down by microbes
into minerals and converted back to earth. Heat, oxy-
gen, organic material and moisture are needed to trans-
form this waste into good fertilizing soil, perfect for your
flower beds.
Oxygen is provided by the ventilation system, and by
tumbling of the composting drum. Additional organic
material is introduced by adding a compost bulking mix-
ture. The waste entering the toilet is approximately
90% water content. Any excess liquid which is not
absorbed will collect on the floor of the unit (evapora-
tion chamber) where it may be evaporated into water
vapor and carried back to the atmosphere through the
venting system. The remaining waste material is trans-
formed into an inoffensive earth-like substance.

The Composting Chamber

The composting chamber is in the form of a Bio-drum
which holds the natural compost heat, provides the nec-
essary mass to maintain a good compost, and is rotat-
ed by turning the handle to achieve perfect mixing and
During mixing, both the input door and the output doors
will remain closed. When the drum returns to the top
dead centre position ready to receive more waste, the
doors will remain open.
A drum stopper, on the right side of the unit  (handle
side) automatically holds the Bio-drum in a top dead 

center position so that it is always positioned to receive
new material.
To ensure that the compost remains moist, but does not
get too wet (between 40 and 60% moisture content is
ideal), any excess liquid which the compost cannot
absorb drains through a screen in the bottom of the
drum directly onto an evaporating tray beneath the
screen, and from there, overflows into the larger evap-
orating chamber. The evaporating tray can be removed
periodically to remove peat moss debris that has accu-

Compost Finishing Drawer

The compost finishing drawer is at the extreme right of
the unit below the composting drum, and just above the
evaporating chamber. Compost from the drum is iso-
lated in the drawer where it is allowed to ‘finish’ com-
posting. For seasonally used units, several drawers of
finished compost are normally removed at the begin-
ning of the season. Otherwise some composted mate-
rial can be extracted into the drawer and left there for
2 months until it is time to remove more compost from
the drum.

Evaporating Chamber

The third chamber is the floor of the Sun-Mar “CEN-
TREX 2000 AF” which forms the evaporation chamber
from where excess liquids are evaporated. You will fre-
quently see liquid in this area.

-  3  -

-  32  -

The key to the success of the “CENTREX 2000 AF Family” lies in it’s three chamber design.  Each of the three cham-
bers; composting, compost finishing, and evaporation have their own independent environments for optimum effi-


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In Electric or AC/DC units, air is pulled through intake
holes at the rear of the unit and down the toilet; over
the evaporating chamber, and up the 2”(50mm) vent
stack which exits from the front of the composting unit
when AC power is being used.
When using the NE or  AC/DC units and AC power is
unavailable, natural draught caused by the chimney
effect combined with a 12 volt fan draws air into the unit
and up the 100mm vent stack.
In Electric or AC/DC units using the AC mode, the evap-
oration process is further assisted by a thermostatical-
ly controlled heating element in a separate sealed com-
partment under the evaporating chamber. This heater
is on when there is liquid in the evaporating chamber,
and largely off when the chamber is dry. The heating
system maintains warmth in the evaporating chamber,
and the indirect warmth assists the composting 

Winter Use

Because “Sun-Mar” units are made of fiberglass and
high grade stainless steel, freezing temperatures will
not damage the composting unit. Composting action
decreases as the temperature drops, so for extended
use, the toilet should be kept constantly at or above
55-60 F(13-15 C) degrees. All exposed 2“(50mm)
vent stack should be insulated to minimize the conden-
sation in the pipe and avoid ice blockages.
In extreme temperatures, an additional source of heat
will also be required. It is also advisable for residential
applications in extreme climates to install an electric
plumbing tape inside the 2”(50mm) vent to prevent
If the compost is frozen in the drum, the unit may be
used periodically as a “holding tank”, until the compost
warms up and the microbes emerge from dormancy.
Space should be made in the drum to accommodate
winter use. The drum should NOT be rotated when the
compost is frozen.

-  4  -

-  31  -

Basic Maintenance Instructions

Sealand toilet and 'Centrex Family' Central Units

The toilet is porcelain and should be cleaned with hot water or bio-degradable products to avoid damage
to the compost. If required 'Compost Quick' or Baking Soda can be used diluted in hot water.

Three  times  a  week  weekly  maintenance:

Turn drum to reveal waste inlet hole through access port and add compost mix at the rate of 1 cup
(250ml) per person per day. (Scoop provided is 2 cups or 500ml)
Rotate handle clockwise to mix contents of Bio-drum and give 6 complete revolutions of the drum - (36-
40  rotations of the handle). Ensure that the drum door opening is in the vertical position at the end
after hearing the 'click' of the catch.

Check  compost  volume  and  condition  in  Bio-ddrum  and:

If the waste in the Bio-drum is too wet add wood shavings to improve aeration.
If composting is too slow add a compost accerant every second week, and ensure that the drum is not
more than 1/2 full. If it is, follow the instructions for the emptying cycle.

Monthly  maintenance  and  emptying  cycle:

Rake out evaporation chamber with rake provided. For units with one, (Centrex 1000, 2000, & 3000
units) the black evaporating tray should be removed, solid matter tipped into the finishing tray and then
replaced beneath the drum screen.
Empty out the collection chamber ready to receive fresh material.

Attention:    the  composting  unit  must  remain  plugged  in  to  an  electrical  outlet  continuously  to  function
odourlessly.    The  AC/DC  units  should  have  both  fans  running  while  used  in  electric  mode  to  prevent  recir-
culation  between  vent  stacks.    If  you  will  be  away  from  the  residence  where  the  composting  unit  is
installed  for  longer  than  three  days,  the  power  may  be  disconnected    while  the  composting  unit  lays  dor-

Composting Drum: Waste and
bulking mixture collect for

Finishing Drawer: Where
compost is put to ‘finish’

Evaporation Tray: Extends the
surface area of the evapora-
tion chamber

Evaporation Chamber: This is
where you will frequently see liq-
uid collecting.


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-  5  -

-  30  -



SUN-MAR Corp. warrants the original purchaser that this toilet is free from defects in mate-
rial and workmanship under normal house or cottage use. SUN-MAR Corp. will furnish new
parts for any part that fails within three years provided that our inspection shows that
such failure is due to defective material or workmanship. Any part supplied by us to
replace another part is warranted for the balance of the original warranty period.

This warranty does not cover:

1. Damage resulting from neglect, abuse, accident or alteration; or damage caused by 

fire, flood, acts of God or any other casualty.

2. Parts and accessories not sold or manufactured by SUN-MAR Corp. or any damage 

resulting from the use of such items.

3. Damage or failure resulting from failure of the purchaser to follow normal operating 

procedure outlined in the Owner’s Manual or in any other printed instructions.

4. Labor and services charges incurred in the removal and replacement of any parts 

found defective under the terms of this warranty.

5. All returns to the factory must by made freight prepaid. All shipments from the factory

are made F.O.B. the factory.

This warranty is in lieu of all other warranties expressed or implied, and no person is

authorized to enlarge our warranty responsibility, which is limited to the terms of this cer-
tificate. The Company reserves the right to change, improve or modify its products without
obligation to install these improvements on equipment previously manufactured.


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-  29  -


Not a common repair.

Follow items in prevention column
for “Drum Too Full”

Drum should never be more than
1/2  full.

Symptom       Cause              Remedial Action                      Prevention

#                            PART                                DECSRIPTION

#                      PART                                  DESCRIPTION

1.        PP-AIRFL-0005XX     AF Transition Piece                      17          PP-INSU0-0187XX     Insulation  (Electric & AC/DC)
2. AO-ACCEP-0481BX     Access Port


AO-THERA-0001BX      Thermosat Sweden

3.      PM-BUSH0-0173       Bushing 1/2”(13mm) OD


AO-THERA-0001AX      Thermostat

4.      PP-GEAR0-0173XX     Nylon Drive Gear


AO-HEATE-0311XX        Heating Element C9286-1

5        AO-SHAFA-0852XX     Stainless Steel Drive Shaft


PM-ALUMS-0811XX       Aluminum Sheet


AO-FAN_A-0315KX         Fan Assembly (Electric & AC/DC)          


AO-DRUML-0469BX        Drum Locker


PP-FAN_a-0315DD         Rubber Gasket 

22        PP-SCRE0-0827XX     Drum Lock Release Knob

8        PP-DRUM0-0800XX    Centrex  2000 Drum


PP-GASK0-0188BX        Rubber U Channel


PP-BEARP-0758RX         Bearing Plate

24        PF-TANK2-0801XX    Centrex 2000 Tank

10    PP-GASK0-0188BX     Rubber U Channel

25        PP-BEARS-0787BX    Bearing Strip

11    AP-DRAI0-0306XX      25mm Drain Assembly

26        AM-DRUMS-0329XX   Drum Screen

12    PF-EVAPT-0789XX      Evaporation Tray


AO-DRUMD-2004XX       Drum Door

13    PF-DRAW1-0764XX     Centrex 2000 Drawer


AO-DRUMD-2004XX       Drum Door


P0-ELECB-0001AX        Electric Box Assembly(Electric and AC/DC)


AO-HANDL-3000XX       Swivel Handle

15    PF-HEAT2-0803XX    Heater Base (Electric & AC/DC)          30        PP-TOPC2-0802CX    Centrex 2000 AC/DC Top
16    PP-GASK0-0188BX    Rubber U Channel


PP-TOPC2-0802BX       Centrex 2000 Top Kit

30        PP-TOPC2-0802DX    Centrex 2000 NE  Top

31   AO-PIPEP-0305XX    100mm Vent Inlet (NE)

Drum Will
Not Turn

Drum Door

(Compost will
drop into the fin-
ishing drawer
even when the
drum is not
being rotated
backwards to
extract com-

Drum fallen from
bearings fallen.

Drum too full

Hinges Stuck

Hinge(s) broken

Have your serial number ready.
If the drum has fallen, contact your Sun-Mar
dealer immediately. We will make sure your prob-
lem is fixed quickly.

See Section on “Compost Troubleshooting- Drum
Too Full”

Drum hinges have compost caked on them.
Spray with vinegar and water solution and clean
with nylon brush. This will push the obstruction
away so the door swings freely.

Call your Sun-Mar dealer  to obtain a replacement
drum hinge.


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-  28  -





1                  PP-TOILS-0208CX   Toilet Seat White

PP-TOILS-0208DX   Toilet Seat Bone

2                  PF-BOWLL-0246FX  AF Bowl Liner

3                  PP-CAP00-0587XX  Tap Cap Bone

PP-CAP00-0587WX   Tap Cap White

4                  PM-SCRE0-0250XX   #8 X 3/4” (19mm) Flat Head 

Philips Screw

5                  PF-AIRFL-0001BX     Toilet Top Bone

PF-AIRFL-0001XX     Toilet Top White




6                  PM-SCRE0-0251BX     #8 X 1/2” (16mm) Stainless

Steel Flat Head Screw

7                  PP-WASH0-0274XX      CKS Plastic Washer 

8                  PP-SNAPC-0273XX      Snap Cap (Bone)

PP-SNAPC-0273WX      Snap Cap (White)

9                  PP-AIRFL-003XX          Toilet Chute

10                PF-AIRFL-0002BX        Toilet Base Bone

PF-AIRFL-0002XX        Toilet Base White

Symptom         Cause           Remedial Action               


System Not
and AC/DC)

Liquid in

Drum Will
Not Stay

Drum Will
Not Turn

Heating Element

Drum Screen

Unit tilted to the

Condensation run-
ning down vent

Drum Locker

Set screw securing
handle to shaft has

Steel pin securing
gear wheel to shaft
has broken

DO NOT use a pressure hose
around the base of the unit.

Install Unit so that weather and/or
groundwater cannot get at the base
of the unit.

Use Proper Bulking Material

Install toilet level or tilting slightly to
the left, DO NOT install the toilet tilt-
ing forwards or to the right. If you
are unsure of the grade of the floor,
install it with a wedge piece.

Remove horizontal sections of vent
pipe and insulate all exposed 2”

When returning the drum to top
dead center position, do not bang
against drum locker with excessive
force. Remember to pull out the
drum locker button before rotating
the drum backwards.

Not a common repair.

Keep composting drum from becom-
ing overloaded. This puts undue
strain on the nylon gear.

Have your serial number ready and call your Sun-
Mar dealer for a replacement. (Detailed instruc-
tions are included with the replacement part)
Please note: Because this part is not easy to
replace, and because there is far less chance
that you will need this part than a thermostat; we
recommend trying to replace the thermostat first.

Use a flashlight to see the screen at the bottom
of the drum. Scrub screen with wire brush. The
overflow drain should be hooked up.

Use a 1/4 - 1/2”(6mm - 12mm) wedge piece
under the right side of the unit to drain liquid
more easily towards the overflow drain of the

Liquid will be clear or yellowish in appearance.
Make sure all vent pipe exposed to the outdoor is
well insulated and there are no horizontal runs.

Have serial number ready and call your Sun-Mar
dealer for a replacement part.

Drill out set screw and replace, or get handle
replacement kit (instructions included).

Have your serial number ready and call your Sun-
Mar dealer  for a replacement Small Gear Kit.


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-  27  -

-  8  -

Symptom         Cause           Remedial Action               


Drains Blocked

Test to determine
whether failure has

Thermostat Failure


System Not
and AC/DC)

Chapter 1


the unit for 

Check Carton
Yourself with
Centrex 2000

Placement of
AF Dry Toilet

1. Rake peat moss away from back two corners

of Centrex 2000 A/F. These are  the“buildup”
areas. If drains are still  clogged, proceed to

step 3.

2. Check drain line for kinks, blockages or 

upward bends. Remove and flush if blockages
present, unkink if bent and ensure that the 
drain pipe is  sloping downward. If your 
drain pipe is in  order, proceed to step 3.

3. Use a wire to poke peat moss out of the drain

assembly at the  back. You will notice if this 
is clogged because you will see a  brown spot
through the opaque  assembly. (Only peat 
would  make it through the drum  screen). If
there is no peat clog, or the problems contin-
ue, backwash the unit quickly with a  hose by 
applying the nozzle to one of the drain 
assemblies and  turning it on and off very 
quickly. If the bottom of the unit is full of

liquid, you may wish to remove some prior to

back-washing. A shop-vac works well.

Pull drawer out and put your hand in the evapo-
ration chamber (Not in the liquid). If there is no
warmth rising from the floor of the unit, your
heating system is not working. It is most com-
monly the thermostat that has failed. If you
notice a lack of evaporation, but there is still
warmth in the heating chamber, see the Liquid
Buildup section on page 26 for solutions.

Have your serial number ready and call Sun-Mar
for a replacement. (Detailed instructions are
included with the replacement part)
If the insulation behind the thermostat access
cover is moist or discolored, or heating does not
work after the new thermostat has been connect-
ed, then the heating element has failed.

1. A clogged drain is  not very likely 

to happen if you rake your 
evaporating chamber 1-2 times a
season (cottage use) and 3-4 
times for continuous use.

2. Use premium 1”(25mm) hose for 

the drain  line. A good hose  will
be less likely to kink. Use elbows
or  fittings around bends  to pre-

3. Use the proper bulking material.

A ground fault circuit interrupter
(GFI) is recommended to protect
your Centrex 2000 A/F  from power
surges that could cause your heating
system  to malfunction.

Your thermostat and fan are the two
constantly moving parts on the unit,
and so are the most likely to fail.
Both are easy to replace.


If there is any visible damage to the carton


the contents of carton MUST be inspected before signing  bill of lading. Damaged units 

should be refused. Call Sun-Mar immediately.


Before signing the shipping papers and dismissing the driver.


ensure that the carton contents have been inspected.


If the shipper has left


Report the damage immediately to the transport company and call Sun-Mar.


Soon after delivery, remove the Centrex 2000 AF carefully 
from the carton


If there is hidden damage, or for any service Questions, contact  Sun-Mar  to 

determine the best course of action.

Check that the carton contains the vent stack (pipe, fittings, roof flashing and diffusor); rake,
drain hose and fittings, extension pipe piece and transition piece. Notify Sun-Mar if you are
missing anything.
i)   Turn the drum handle clockwise to rotate the Bio-Drum for mixing and aeration. (The drum 

rotates counter-clockwise and the drum door closes). TThhiiss  iiss  hhooww  yyoouu  wwiillll  rroottaattee  tthhee  ddrruum


ii)   Lift and remove the access door  and rotate the drum until the drum opening is opposite

the access door for adding a compost bulking mixture. TThhiiss  iiss  hhooww  yyoouu  wwiillll  aadddd  bbuullkkiinngg  

miixxttuurree  ttoo  tthhee  ddrruum


iii)   Plug the unit’s electrical cord into a standard electrical outlet, and feel the air movement 

from the vent outlet at the top left of the unit to ensure the vent system is working prop-
erly (Electrical  or AC/DC)

v)    Pull out the compost finishing drawers at the bottom left and right of the unit.
vi)   After the unit has been plugged in for ten minutes, place a hand on the floor of the 

evaporating chamber (the inside floor of the unit) to check it is warm to the touch, and 
that the heater is working properly.

vii)   Affix the “WARNING/CLEANING” sticker to the underside of the toilet seat cover, and check 

that another is on the access port of the composting unit.

viii) Check the AF “Dry Toilet” for any damage.

Ensure that the floor joists are not in the way and that there is an unobstructed 10”(254mm)
diameter passage from the underside of the AF “Dry Toilet” to the top of the transition piece.
The 10”(254mm) hole should be centered 13”(33cm) from the back wall  and at least 6.5”
(165mm) from the side wall in the room where the toilet will be installed.
The transition piece on the top of the composting unit should be located so that the center line
of the transition piece is directly below the center of the 10”(254mm) circular cutout which will
be made in the bathroom floor above. The transition piece should be completely vertical on the
composting unit.


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-  9  -

-  26  -

Symptom       Cause               Remedial Action              


Fan Noisy
and AC/DC)

Fan Not
and AC/DC)

Lack of 

ing Liquid

Fan damaged in
shipping, or bearing
are beginning to
wear if it is rattling.

Debris in fan or
Mechanical Failure.

Increased usage.

Failure of heating
system (Electric and

Mineral salts may
have accumulated
in the evaporation
chamber over a few
years, reducing
evaporation rates.

Overflow drain not
hooked up

Unit tipped forward

3. If it is a vibration noise, you may  need to tie 

down the top of the  stack with guide wires 
and bracket  the pipe that runs up the side of
the structure.

Have your serial number ready and call  Sun-Mar 

The amount of liquid varies substantially between
installations. The overflow drain needs to be
installed on all Centrex 2000 AF models as you
will have overflow in DC mode and with heavy use
on AC mode.

Check “heating not working”.

To get rid of these, fill the evaporation chamber
with very hot water. Leave overnight.
Drain all Liquid through the overflow drain by tip-
ping the unit up (make sure overflow is hooked
up first)

Connect overflow safety drain (See also increased
usage above)

Check and ensure that the unit is level or tilting
slightly towards the left by placing a 6mm -12mm
shim piece under the right side of the unit.

The fan is a continuously moving
part which will eventually have to be
changed. Do Not turn on and off

Install the safety drain. If the unit is
being used in DC mode there will be
very little evaporation.

Rake evaporating chamber vigor-
ously at spring startups for cottage
use, and once every other month for
residential use.


Chapter 2



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when drum

Fan Noisy
and AC/DC)

Downdraft is dependent on wind
direction, as well as natural
obstructions, etc.
Initially, install the vent 20-30”(60-
90cm) above the peak of the roof.
If symptoms occur, add lime or a fil-
ter box.

Follow “Ongoing Maintenance” and
use proper bulking material.

Clean the AC fan with a small brush
and/or compressed air nozzle once
every 2-3 years in cottage use, or
once a year residentially. To do
this, remove the fan assembly by
taking off the snap cap covers and
unscrewing the screws which hold it
The entire assembly will then simply
slide out. This will prevent wear
and lengthen the life of your fan.

Cleaning should not be necessary
for the DC fan.

Symptom       Cause               Remedial Action              


1. Vent stack not

installed  even 

with peak of roof.

2. If vent stack is 

installed above 
roof peak, natu-

ral obstructions,

such as tall
trees, being 
located in a
valley or close to
a hill  may be 
causing down-

Compost is 

Fan damaged in
shipping, or bear-
ings are beginning
to wear if it is rat-

1. Check that the vent is installed 20-30”

(60-90cm)  above  the peak of the roof. If

not, extend the vent. Guide wires may be 

2. Add lime to the evaporation  chamber - as 

much as you  think necessary. You will have 

to rake more often if you do  this. You can 

also add lime to  the compost if desired, but 
no more than 1 cup(250ml) per week  as it 
may  upset the PH balance  in larger 

3. Sun-Mar has a filter box available which will

filter the ammonia out of the 50mm  stack 

vented air in a downdraft situation. Call    
Sun-Mar  for  details.

Begin following: “Compost Troubleshooting” sug-

1. If the fan is rattling, it may need to be 

cleaned or the bearings are worn and the fan 
needs to be replaced.

2. A hum is the normal sound the fan will make.

If you are in a very quiet setting it will be 
more noticeable. If this is the case, consider
purchasing an AC  fan speed control so that 

the fan may be turned down when the noise 

bothers you. These are not available for our 

DC fans, but should not be necessary.

3. If it is a vibration noise, you may need to tie 

down the top of the stack with guide wires 
and bracket the pipe that runs up the side of
the  structure.

- 10 -

- 25 -


background image

Urine Odour
2000 AF 

Symptom       Cause               Remedial Action              


In Your Kit

Installing the
AF Toilet


1- Owners Manual

1- 1  1/2” (38mm)Roof Flashing (Electric & AC/DC)    

1- Warranty Card

1 - 4” (100mm)Roof Flashing  (NE & AC/DC)  

1- Evaporation Tray

6- 2”x30”(51mm x 787mm) PVC Pipe (Electric & AC/DC)   

1- 8’4”(256cm  x 25 mm) Drain Pipe               1- Centrex 2000 Hardware Kit
1- Rake

1- 4”(100mm) Diffusor  (Electric & AC/DC)     

1- AF Transition Piece 

1- 6”(150mm)  Diffusor  (NE & AC/DC)    

5- 4” x30” (100mm  x 785mm) ABS Pipe (NE & AC/DC)   
1- Centrex 2000 NE Hardware Kit (NE & AC/DC)          
1- 12 Volt 2.4 Watt Fan (NE & AC/DC)    

1- 44”(112cm) Extension Pipe Piece

1- AF Silicone Kit

The AF “Dry Toilet” comes preassembled. For the purpose of explanation,

the toilet base is the bottom of the toilet which is secured to the bathroom
floor, the toilet chute is the black inner section (shown in Fig. A) that fits
through the floor and is attached to the toilet top, the toilet top is the upper
part of the toilet that attaches to the toilet base, and the bowl liner which is
the black removable funnel shaped piece below the toilet seat.
To install the AF “Dry Toilet”, follow the procedure outlined below:
1. To locate the position of the hole, place the toilet chute in the desired
location and trace the 10”(250mm) diameter cut out in the bottom of the toi-
let base on the floor in the bathroom. (See Fig. A)
2. Drill a 1/2”(6mm) hole on the front of traced line and then check under
the floor that the hole will be clear of floor joists and will line up with the com-
posting unit below. (See Fig. B)
3. If the position is correct, complete the cutting of the 10”(250mm)
diameter  circle with a jig saw. (See Fig. C)
4. Center the toilet base over the 10”(250mm) diameter hole that has been
cut out of the floor and securely attach to the floor by using the four 5/16” by
2 1/2”(8mm by 64mm) lag bolts that are provided with your kit. (See Fig. D)
**Prior to finishing the toilet installation, it is a good idea at this time to do a
pre-assembly check to see if you will need any extension pipe 

Place transition piece(Fig. E)  into the waste inlet hole on the top of the
Centrex 2000 AF composting  unit. Make sure that the transition piece
is completely vertical on the unit, or completely vertical. It is important
that the transition piece is not tilted so that waste can drop directly into
the composting drum.

Fig. E

Fig. D 

Fig. C

Fig. B

Fig. A

Horizontal runs or
downward slopes on
pipe are causing con-
densate to block
50mm vent pipe.

Fan has failed (AC or
DC mode)

Device other than Sun-
Mar diffusor is
installed on top of the
vent stack
Room where unit is
located is airtight.

50mm vent stack has
too many bends
and/or horizontal

Not enough air being
pulled down the dry

Re-install the vent so there are no longer any low
points where condensate can collect. If re-instal-
lation is not possible, drill a small hole in the bot-
tom of the low point (preferably outdoors) to
allow condensate to drain. (Note: watch for icing
in winter at this hole.)
Have your serial number ready and call Sun-Mar
for a replacement. Instructions are included with
the replacement fan.

Wind turbines or vent caps may be discouraging
air movement. If so, replace with a Sun-Mar diffu-

1. Hold a lighter up to the air intake holes on the

back of the unit. Air should be drawn into 
the holes. If air is not easily pulled in, check 
venting for too many bends or horizontal 
lengths and/or provide more ventilation to the

2. Install fresh air intakes on any competing 


1. Re-install the 2”(50mm) vent stack to reduce 

the  number of bends/eliminate horizontal 


2. If the vent stack cannot be further straight-

ened, remove the AC fan assembly and 
reduce  the amount of recirculating air by 
adjusting the fan gate (see page 14).

Two 3”(75mm)  diameter air intake holes covers
are supplied with the hardware kit. One or both
of the air intake holes at the rear of the unit, may
be covered so that more air is pulled down the

Install wall brackets on vent pipe
to prevent settling. DO NOT
install horizontal runs as liquid
will collect and block ventilation,
causing odour.

The fan is a constantly moving
part and has a finite service life.

Wind turbines or vent caps
should not be installed on or,
instead of a Sun-Mar diffusor.

Install your Centrex 2000 AF  in
an area  with plenty of ventila-
tion and watch for competing
appliances such as bathroom
fans and wood stoves.

Install the vent with minimal
bends (total bends should equal
no more than 360 degrees) and
NO horizontal or downward

Covers should only be inserted if
they are needed, because inser-
tion reduces airflow over the
evaporation chamber, which in
turn reduces evaporation per-

- 11 -

- 24 -

Most problems are prevented through proper maintenance and the use of proper bulking materials in the toilet.  If you
do have a problem which may be a mechanical or installation problem, this Trouble Shooting section will help you solve
it.  If you still have further questions, contact technical service at Sun-Mar  for advice .

Chapter 5



background image

-  23  -

-  12  -

Symptom        Cause                Remedial Action                      Prevention


-compost too dry

-compost anaerobic


waste added

-foreign material


1 .To get rid of flies, you can use  any  pesticide

that is used on your garden. Pesticides used  
for garden use are not anti-bacterial so are

safe  to use on your compost. If you prefer not 

to  use a  pesticide in your compost, the unit 

should be   cleaned out completely and washed

with soapy water to kill any remaining eggs.

Once the unit is washed, it should be rinsed well 

to remove all traces of soap before restarting
the compost.

2. If using a pesticide to kill the insects, it may

be purchased from a local garden center or
hardware store.

3. If using a liquid, sprinkle about 1/2 cup    

(125ml) of the mixture directly over  the 

compost. Using a spray bottle, apply  through-

out the entire toilet (finishing drawer, evapo-

rating chamber, drum, out side of drum)  until 

the fly population is eliminated. Open a 
window or  door  to ventilate  the  room while
applying and  keep children and pets away
from the  area for a  few hours  after 
Repeat if you  see another  fly after the initial 

Application of a pesticide  in a Sun-Mar com-
poster is not a health concern because all Sun-
Mar units are vented.

1. Keep compost moist. In order to 

determine a good level of moisture,
shine a flashlight into  the drum.
The compost should have a slight

gloss or shine. If it does not, add 
warm water to it until it reaches this 
consistency. Fungus gnats tend to 
be attracted to a dry compost, due
to the fungus which begins to form
on the surface when it dries out. A 

good, moist compost  will not be 
attractive to flies.

2. Do not add topsoil  from the   

ground, composted matter, or 

kitchen scraps to the toilet. Flies 
may be  present in, or attracted
to these items.

3. If toilet is installed over an old sep

tic line,make sure that the lines are 
well sealed. Insects find unused 
lines  attractive.

4.See “Compost Remediation” if the 

compost smells- anaerobic compost 
will attract flies and drastically 
reduce the performance of your 
composting unit

5. Use  a  mixture of peat moss and 

non-antibacterial wood shavings.

Place the toilet chute into the toilet base in the bathroom. If the toilet chute extends 1-2”(25 - 50mm)
into the transition piece, then no extension pipe pieces will be required. If the transition piece does not
extend far enough up to meet the toilet chute, then one or more extension pipe pieces will be needed.
These minimum 44”(112cm) pipe sections can be cut down to the correct length, so that when assem-
bled and placed in the transition piece, they extend 1-2”(25-50mm) into the toilet chute. After taking
into account the overlap, each pipe piece provides an extension of about 41”(104cm).

A pipe section, which comes in two halves, can be cut to the correct length, by cutting the required
amount off the straight ends of each half with a hack saw.
It is easier to cut pipe sections to length before joining the two halves together. After cutting, clean up
the edges with a sanding block and coarse (40-60 grit) sandpaper.
Before joining the two halves of the pipe pieces, spread a bead of silicone caulking from top to bottom
along the inside of both halves of pipe pieces (so that the inside of the pipe section will be sealed).
Press the two halves together, and secure them by screwing  the self tapping screws provided into the
pre-drilled holes. Run a finger or spatula up along each joint inside the chute to remove any excess sili-
cone. Ensure that when the pipe pieces are assembled together, and the bottom piece is placed in the
transition piece of the composting unit, so that the top of the transition piece extends 25-50mm over the
chute or extension pipe piece.

Pre  Assembly  Check: Before finishing the installation, make sure everything fits
together properly. The top of the pipe piece is belled out to accommodate the
toilet chute. Place the transition piece in the cut out provided on the top of the
composting unit. Place the pipe pieces, if any, inside the transition piece. Next
lower the toilet top onto the base so that the chute projects 1-2”(25-50mm) into
the pipe piece or directly into the transition piece if no pipe piece is used.
Ensure that the toilet top is properly located over the toilet base, that the chute
is completely vertical, and that the screws to attach the top to the toilet base, line
up properly. ( Fig. A) If the pre-assembly check appears OK, then disassemble
and reassemble each piece as in the pre-assembly check(see above).
To assemble the toilet top with the chute, line up top with the chute and fasten
the four screws around toilet opening and cover with the snap caps (Fig B).
Insert the toilet chute into the toilet base until the toilet top rests on the  base
(Fig C). When reassembling use silicone caulking at the joints where the toilet
chute sits inside the extension pipe piece, where the extension pipe piece sits
inside the transition piece and where the transition piece sits inside the compos-
ing unit. Use a finger or spatula to remove any excess silicone.
Next, line up the two pre-drilled holes which go through the front of the toilet top,
through into the toilet base, and insert the two screws without tightening them.
With these front two holes secured, tilt the rear of the top down over the base
until the last four screws are located. Screw in all six screws, making sure not to
over-tighten, and push on the plastic caps over the screw heads. Attach the toi-
let seat by threading the nylon screws through the toilet seat hinge and into the
holes into the toilet top. Put the black removable bowl liner into place under the
toilet seat.

if an
Pipe Piece is 

and Installing
the Extension
Pipe Pieces
(If Needed)

Finishing the
AF “Dry

Fig. A 

Fig. B

Fig. C


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-  13  -

-  22  -

Symptom       Cause                Remedial Action                       Prevention

Waste not
Down at all


If many large
lumps have
formed in drum,
you will need to
remove them or
break them up
with the rake tool.
Follow the pre-
vention column to
ensure this does
not happen.  

Drum Too

Note: The drum is
too full when it is
over 1/2 full, and
the door is not
closing properly. 

Antibiotics being
used for more than
a few weeks on a
continuous basis
may kill bacteria.

Compost Too Dry

Over-Rotation of

Peat moss used as
bulking material with
no wood shavings.

Compost not emp-

tied  into finishing

drawer  in a timely

Waste added

Empty drum. Hose out inside of drum. Restart
compost according to “Initial System Startups”.

Follow instructions for “Compost Too Dry” above.
And also add 1-2 QUARTS(2 liters) of warm

also add 1-2 QUARTS(2 liters) of wood shavings.

Begin using 70%  wood shavings, 30% peat
moss as bulking material.

1. Remove compost until drum is only half full or 

less. Rotate compost thoroughly to aerate,
and add compost accelerant if available.

2. If you need to dump more than one drawer of

compost, and you do not already have a suit-
able backyard compost heap, you may  try an 
open-slatted wooden crate (such as the kind 
used to pack age fruits and vegetables).
Layer compost with bulking material and leave
crate outside for around 2 months to finish 

When used normally, antibiotics will
only slightly slow compost. Add
compost accelerant during this peri-
od to accelerate compost action.
Urinating elsewhere during this peri-
od will also help minimize the dam-
age to the compost.

Follow recommendations for check-
ing and adding moisture in “PERI-

Drum should be turned three times
a week, 6 rotations each time; once
before departure for weekend use.

Use proper bulking material.

When drum is 1/2 full, remove some
compost to the finishing drawer by
rotating the drum backwards, to
avoid surprise over-filling of drum.
Do NOT let drum get above 1/2 full.
(The drum is 1/2  full when the
level of the compost reaches 4-
6”(100-150mm)  below where the
drum door hangs) This will lead to
lack of aeration, and anaerobic
compost, and the inconvenience of
having to remove more than one

Do Not add kitchen or garden

The Centrex 2000 AF composting unit has a 3”(75mm) diameter air intake hole at the rear of the unit,
just above the floor of the evaporation chamber. A 3”(75mm) intake cover is supplied with the  hard-
ware kit in the composting unit. The air intake can be removed and replaced with the 3”(75mm) intake
cover if it proves necessary to pull more air down the AF “Dry Toilet” chute. This cover should only be
inserted if it is needed, because blocking the air intake will reduce the airflow over the evaporation
chamber, which in turn reduces evaporation performance.

If the air intake cover is in place (See “Adjusting the Air Intake Covers”
above), but the toilet is more than one extension pipe piece above the com-
posting unit so the fan is unable to draw air down through the toilet chute,
then it is necessary to vent the toilet directly. The toilet itself should be
vented as follows:
i)   Obtain sufficient pipe and fittings for the vent using either 3”(75mm)

sewer  pipe or plumbing pipe.

ii)  Trace the outside outline of the pipe on the circular section at the top 

and rear of the toilet top at  either the left or right of the toilet top 
depending  on  which side it is more convenient to vent from.

(See Fig. A)

iii) Cut out the hole by first drilling a hole in the circumference of the traced 

outline, and then carefully using a jig saw to complete the circle. Sand 
to enlarge or smooth off the edges if necessary.

iv) Cut a short length of pipe and glue it into a connector, with 1/2” (13mm)

of pipe protruding from the connector. Place this protruding end in the 
newly  cut hole to locate the base of the vent stack. (Fig. B)

v)  Erect the vent stack as vertically as possible following the same rules as 

outlined on page 14, in the vent pipe location section.

vi) If it is not possible to make this vent vertical or close to vertical, a 12  

Volt fan may also have to be installed in this vent stack. Since the 12 
Volt fan comes  in a 12”(300mm)  length of 4”(100mm) sewer pipe,
transition coupling will  be needed if 3”(75mm)  pipe has been used.

Remove the bowl liner in the toilet top, and drill out a large number (15-20)
holes 1/4”(6mm) or bigger at the top rear of the chute piece no more than
3”(75mm) down from the top edge. (See Fig. C)
These holes will enable the vent on the top of the toilet to draw air up the

The 1”(25mm) Safety drains at the left of the “Centrex 2000 AF Family”, exit to both the front and
back. To connect one of the drains, (whichever is convenient), remove the plug, attach the 1”(25mm)
hose (included) and secure with a hose clamp. Ensure there are no kinks or upward bends in the drain

Adjusting the
Air Intake

Installing the
Vent on the
AF “Dry

Cutting Holes
in the Toilet


Fig. A

Fig. B

Fig. C


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-  14  -

-  21  -


Vent Piping

the fan gate
(Electric and


The following are possible options to take care of the liquid:
- Use a container which is emptied periodically (water jug or 

small  barrel). This ensures a closed loop system.

- Feed into a lined pit filled with gravel and sand. Such a

recycling bed also ensures a closed loop system.

- Feed into a small cesspit or “french drain”.
-Plumb into an existing septic or holding tank line.

Installation should be in accordance with applicable local regu-

Piping can be installed up the inside wall; through the wall at a slight angle and  up the outside wall. The
choice depends on ease of installation, visibility, and (especially if the toilet is to be used consistently
through a cold winter), the necessity of insulating all exposed vent pipe.

The vent on the right is a 4”(100mm)
on-electric vent.
All others show possible 2”(50mm)
Centrex 2000 (electric) vent configura-

If you believe that there may be a downdraft outside of the
building, it may be a good idea to remove your fan assembly
prior to installation and set the fan gate to ‘0’ to prevent urine
odour in the bathroom. The fan gate is factory set to ‘3’, which
recirculates air within the unit. If there is a downdraft you may
get blow back into the room where the unit is installed. When
setting the fan gate to ‘0’, you may lose some evaporation so it
is also wise to hook up the emergency drain.
Piping and fittings are of standard 2”(50mm) PVC thin wall tubing(central vacuum) and/or 4”(100mm)
PVC thin wall pipe. Additional pipe or fittings can be purchased from a building supply dealer. If you can-
not find them near your location, you can substitute schedule 40 pipe and use a rubber coupling to join
this pipe to the unit.
i)    Minimize the number of sharp angles in the 2”(50mm) vent as each reduces vent efficiency. The 

4”(100mm) vent  should be installed as near to vertical as possible. If it is  necessary to have 
angles in the 4”(100mm) vent pipe 45 degree angles are used whenever possible. On the  4”

(100mm) DC stack, bends  should be limited to 2 - 45 degree angles. This will necessitate the 

installation  of a 12 volt fan.

ii)   Do not lead the 2”(50mm) vent pipe downward or horizontally at any point. This may lead to  the 

Symptom       Cause                 Remedial Action                      Prevention

Too Wet

Your compost 
is too wet when 
there are 
standing pools
of liquid.
Compost will
smell of sewage
and is 

Too Dry

Compost is too
dry when com-
post looks flat
and brown rather
than rich and

Waste not
Down at all

If this is the case,
the drum will fill
up quickly

Compost porosity is
poor. Too much
peat moss has been
used as a bulking
material. This is
compacting, pre-
venting liquid from
draining through,
and leaving no free
air space for oxy-
Drum screen

Moisture not being
added periodically
or before departure
on cottage units.
Toilet not used for
urination .

Insufficient bulking
material or not
enough peat moss.

Insufficient Microbes

Temperature around
unit under 15C

Bleach or other
anti-bacterial chemi-
cals added.

For an immediate improvement in porosity add
about 2 liters of wood shavings, of any kind
(except cedar, cypress, juniper, bamboo, teak,
redwood, eucalyptus, sugar cane, or any other
woods with anti-bacterial properties) to the drum.

On an ongoing basis, change bulking material  a
mixture of 60% wood shavings and 40% peat
moss mix.

Remove the finishing drawer. Scrub screen
(which will be visible with a flashlight on the bot-
tom of the drum) with wire brush. The overflow
drain should be hooked up.

Add 2 to 4  litres of warm water to compost in
order to bring it up to appropriate moisture level.

Peat moss retains moisture. 40-60% moisture
content is ideal for aerobic microbes to thrive.

Add compost accelerant or unsterilized black
earth from a garden center.

Install heat source to increase temperature.
Temperature should be kept above 13 -15C con-
stantly if toilet will be used on an ongoing basis.

Empty drum. Hose out inside of drum. Restart
compost according to “Initial System Startups”.

Use  40% peat moss, 60% wood
shavings as a bulking material.

Follow section on moisture in 

Use toilet for urination.

Add correct bulking material.

Be sure to add compost acceler-
ant  at startups.

Install unit in warm area. The
warmer the area, the better your
compost will be!  If evening tem-
peratures fall below the prescribed
temperatures on a residential unit,
consider installing a heat source
on a timer for evenings.

Never add bleach or cleaning


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-  15   -

-  20  -

This chapter will deal with problem that may arise with your compost,  what is required to make your compost healthy
and how to correct problems if they arise.  

Aerobic Compost Requirements

In a Sun-Mar, a good compost is predominantly aerobic, which
means that oxygen is available for aerobic bacteria throughout
the Bio-drum. Aerobic bacteria consume waste quickly and
odourlessly to produce carbon dioxide and water vapor and
leave behind a small fraction of the original waste volume in
the form of basic minerals. The end compost is a mix of valu-
able minerals and bulking material that has not decomposed.

To work effectively to break down waste, aerobic bacteria need
oxygen, moisture, available carbon (from the bulking material),
and warmth.

In a Sun-Mar, oxygen is provided by the tumbling of the drum
and the bulking material leaving free air space within the com-
post. Moisture is provided by the waste, and is made available
to aerobic bacteria by the moisture retention properties of the
bulking material. If the compost is too dry, add warm water.

In summary, to keep the compost aerobic, it is important to
rotate the drum, add bulking material, and keep the compost


Lack of oxygen becomes a problem where:

- Too much moisture eliminates the free air space,
- A lack of bulking material limits free air space,
- Aerobic bacteria use up oxygen in the compost.

Lack of oxygen causes the compost to become increasingly
anaerobic, which means that aerobic bacteria are displaced by
anaerobic bacteria. Anaerobic bacteria work slowly and pro-
duce undesirable ammonia, hydrogen sulphide, and methane.
Consequently, the maintenance of ‘free air’ space by periodi-
cally rotating the drum and adding the right bulking material is
very important in Sun-Mar units. Excessive rotation is not
helpful and can harm the compost by disturbing the bacteria
too much.


If there is too much moisture, and the compost is approaching
saturation, oxygen is pushed out and anaerobic activity pre-
dominates. On the other hand, if there is too little moisture,
aerobic activity slows. For this reason, it is important to main-
tain adequate moisture levels (40-60% moisture content is
ideal). Generally, if you shine a flashlight in after mixing, there
should be a slight sheen of moisture on your compost.


Too little warmth will cause aerobic activity to slow. Below  13-
55F(15C) degrees, microbes will go dormant and composting
will stop. Composting speeds increase dramatically with tem-

Characteristics of a Bad Compost

If your compost is over 8 weeks old and it exhibits one or more
of the following characteristics , then an operating change is


Extraction required too often (under 4 



Large Lumps present in compost


Compost muddy or clay-like


Flies present (this may also be a problem

with foreign matter being added to unit; see
section on flies)


Compost has strong unpleasant smell of

sewage when drum is turned.


Toilet paper present in finishing drawer


In using this troubleshooting section, you should follow reme-
dial actions in the order that they are given, unless you are
sure of the problem. You should see improvement in a week,
and your compost should be back to normal in 2-3 weeks. If
it is not, make sure that “Ongoing Toilet Maintenance” is being
followed and check the mechanical troubleshooting section.

vent pipe being blocked by condensation which would cause a urine smell in your bathroom.

iii)  All connectors in the vent pipe should be sealed. Use  silicone  for  the  connection  of  the  vent  stack  to

the  toilet  in  case  the  composting  unit  has  to  be  moved  or  you  have  to  access  the  fan. PVC cement 
may be used in the rest of the stack installation if desired.

iv) All exposed 2”(50mm) vent pipe should be insulated with the foam insulation. This is  especially 

important for winter or residential use to prevent condensation.

v)  The Sun-Mar 12 Volt fan is fitted inside a 12”(300mm) length of 4”(100mm) vent pipe for easy 

installation, should it be needed. It is installed by either cutting out a section of the vent immediately 

above the composting  unit, or by raising the vent stack off of the composting unit and inserting the 
fan section. The fan can be used with a solar panel and 12 volt battery, or by purchasing a 12 volt 
adapter from your local hardware store and simply plugging it into the wall.

As shown in the installation, the vent stack should
end about 20-30”(60-90mm)  above the peak of
the roof so that it is less subject to downdraft.
Where the piping is taken through the roof, the roof
flashing provided should be used to seal the instal-
lation. Insert the vent into the bell of the roof flash-
ing and slide the roof flashing down until it lays
evenly on the roof. Slip the upper edge or the roof
flashing flange under the shingles.

Outline the

flashing on the roof. Raise the roof flashing and
apply silicone sealant or roofing tar inside the out-
line. Slide the flashing back into place and firmly
press onto the sealant. The flashing is properly
placed when the top part of the roof flashing flange
is tucked under the shingles and the lower portion
is sealed on top of the shingles so that water sheds
easily. Secure the flashing with corrosion resistant nails at each corner and along sides. Any exposed nails
should be sealed with silicone caulking.

The diffusor provided with the unit is a simple device to
be installed at the top of the vent stack with the larger
pipe protruding above the smaller. To install, simply
glue the diffusor on the topmost section of vent pipe.
The diffusor design encourages updraft, and discour-
ages wind and weather from going down the vent stack.
Unlike wind turbines, diffusors are less likely to freeze
up in winter, and are more effective in calm weather.

A ground fault circuit interrupter (GFI) is recommended to protect your
composting unit from electrical problems.
This may be installed directly on the wall socket or at the circuit breaker.
An example is shown in the picture at the right.


Leading the
through the

The Diffusor

(Electric and

Chapter 4

Compost Troubleshooting


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- 19  -

-  16  -

Ongoing Toilet Maintenance

The procedure below is designed to keep the compost:

- Moist, but not too wet

- Well aerated and mixed
- Well balanced and aerobic 


1 cup


250ml) or 2 handfuls of a mixture of 40% peat moss and 60%  non-

antibacterial wood shavings  to the Bio-Drum per person per day of use.

Turn Handle 

to rotate the drum a minimum of 6 complete revolutions every

second day when in use. Pull the drum locker button and turn the drum 1/2 turn
past its’ resting position to level the compost inside the drum. To prevent a mess,
DO NOT  forget  to  return  the  drum  opening  to  a  position  under  the  waste  pipe.  


the unit if you are leaving for a period of more than a few days. If you

are leaving one weekend and coming back the next, you may unplug the unit. If
you are leaving for a period of more than a few days, or the compost appears dry,
add approximately 1quart(2 liters) of warm water to keep the compost moist.


compost into the finishing drawer when the drum is 1/2  full. It is 1/2

full when the compost reaches a level about 100-150mm  below the bottom of the
drum door when the door is open.
To empty some compost into the drawer, pull the  drum  locker  button and rotate the
handle counter-clockwise (to turn the drum clockwise). Turn at the same speed you
would normally do for mixing. This will fill the finishing drawer. Compost in the
drawer should then sit in the drawer, in the unit to finish composting for at least 2
months before the drawer is emptied. If necessary, use the rake to level the com-
post in the drawer. If there is not enough compost in the drawer, turn the drum
backwards (clockwise) again1 rotation.
We recommend storing compost in a container before using.

If your unit is used seasonally and is not used heavily,
you may not have to remove any compost at all during
the season.  If so, follow “Annual Startups”.

- Maintains the carbon/nitrogen 


-  Absorbs liquid
-  Helps oxygen penetrate for aerobic


-  Mixes and oxygenates the compost

-  unplugging unit will conserve power 

and keep compost from drying.

-  addition of water helps keep the 

compost moist

-  Moves some compost to the next 

stage for finishing

-  Ensures that the drum does not get 

too full

-  Provides extra time for composting 

to be completed

Every Sun-Mar AC/DC  and NE model comes with a 12 Volt Fan for installation in the 100mm stack. Its
installation is  required in the following situations:

-If you are installing both 2”(50mm) and 4”(100mm) vent stacks (prevents downdraft from

the 2” or 50mm vent)

-If you are in an area where you are subject to downdraft
-If you are using the unit residentially 
-If you need to install the vent stack with bends 

We include it because many AC/DC owners do install both vent stacks. It may also be installed later if you
wish simply by cutting a section out of your vent and replacing it with the fan.

To install the fan initially, pick a spot on the stack that you can
reach easily. In order to get the best evaporative performance
from the fan, install it near the composting unit  if possible
(remember, the fan will still not be enough to evaporate all liq-
uids in a non-electric or DC only environment). Once you have
placed it where you wish, use silicone caulking, or rubberized
couplings, to make the installation airtight. Do not use  glue as
you may need to change the fan at a later date.

The 12 Volt Fan may be powered with a battery that is connected
to a generator, solar panel, or other alternative energy system.
For use in AC, purchase a 12 Volt to AC Adapter from any electri-
cal store and snip off the female end - wire the positive wire to
the red wire on the fan, and the negative wire to the blue wire on
the fan. Tie them off with small wire connectors, and plug your
AC Adapter into the wall.

The 12 Volt Fan should be continuously running if used, as if it is
not running it will act as a block in the vent stack.

12 Volt Fan
(AC/DC and

Action                                                 Reason for Action


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-  17  -

-  18  -

Annual Start Up (seasonal units only)

Many units are only used regularly throughout the summer. For such seasonal units Sun-Mar recommends that the
following start up procedure be followed at the beginning of the season.


Reason for Action


the compost that had been left in the finishing drawer, and use the rake

to clean out the evaporation chamber.


additional drawers of compost (if there is more than 6-8” or 150-

200mm in the drum), by releasing the drum lock (white button on right side of
unit), and rotating the drum clockwise (the handle turns counter-clockwise) to
extract compost into the drawer. (At the beginning of the season, it will all be fin-
ished compost) Empty the drawer and repeat extraction cycle until the level in the
drum is reduced to about 6”(150mm).


1 gallon(4 liters) of warm water.

As an option for optimal composting,

Add composting accelerant. We do not recommend using topsoil as it may contain
fly larvae.

Your fertilizer is ready.

-  This is a good time to remove peat 


Frees space in the composting   
chamber  for the new seasons com-

- Raises moisture level

- Even though the compost still has

microbes in it, you may want to start 
the  year by replenishing your batch 
of  microbes.

Chapter 3

Start Up and Use

Initial System Start Up

Begin operation by carrying out the start up procedure described below, and then continue with the “Ongoing
Toilet Maintenance” routine. It normally takes six weeks before a compost is properly established. You will know
this has happened when:

-  Compost Volume increases more slowly

-  Compost turns black and becomes loam-like
-  Toilet paper decomposes within a few days

Action                                                      Why?

-Provides carbon base and initial mass
for compost.
-Adds necessary microbes which will
breakdown the compost.
-Moistens carbon base

-The unit is ready for use

-Until the compost is active, some peat
moss may fall through the screen or
drum door into the evaporating chamber

Extends the surface area of evaporation

8 gallons(30 liters) of bulking mixture (60% shavings and
40% peat moss)  to the drum.
Compost accelerant

About 1gallon(4 liters) of warm water into the drum

Fan and heater are operating

Loose peat moss from the evaporating chamber until the
compost is established, which takes approximately 6 weeks.

Black evaporating tray under drum screen to the left of the

Periodic Check Up

Once your unit has been through initial or annual start-ups, and ongoing maintenance procedures are being followed,
Sun-Mar recommends a system of periodic checks be undertaken.

Action                                          Reason for Action


solid debris from the evaporation chamber, making sure to rake from the

rear of the chamber, including the back two corners nearest to the drains of the
unit. Raking should occur on a twice yearly basis for cottages (best done at annual
startups and half way through the season), and a bi-monthly period for continuous


your compost moisture level on each visit for cottage users and once

every two weeks for continuous users. This can be done by shining a light into the
Bio-Drum. The compost should have a slight gloss  or shine to it. A moisture meter
may also be used if so desired. Range should be 4-6, which represents 40% to


1 gallon(4 liters)  of warm water down the toilet.

- Ensures drains cannot get plugged and 

evaporation is improved.  

-  A good compost is between 40% and 

60% moisture content.

- Prevents lumps, ensures toilet  paper 

breaks  down quickly. 

- Prevents insects
- Ensures waste piping remains free-



1. Do 


add or clean the toilet bowl with chemicals. Chemicals will kill the bacteria.


, clean the bowl hot water and baking soda or a weak vinegar and water solution.

2. Do 


add plastic, glass, metal, cleaning fluids, cigarettes. Add only waste and bulking material.

3. Kitchen or garden waste are 



Toilet paper is a good source of carbon and should be added after use.







Although the start up instructions remain the same no matter what your application, different situations
will require different actions and this chapter will explain what they are.