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    Clivus Multrum™ Troubleshooting Guide

    Where to start..

    There are 4 key consideration when addressing faults with composting system to need to be inspected. Most composting system have the following design aspects that are key

    Ventilation systems is used to provide the following

    1.        Odour-free operation
    2.        Oxygen supply to the composting process
    3.        Drying or evaporation of liquids, keeping in mind for composting to take place the compost its self must have no less than 45% moisture
    4.        Preventing insects from entering the composting system by providing directional air flow
    5.        Is a code requirement

    Moisture management systems (leachate drain)

    1.        Leachate in most system is the residual moisture left over from the biological composting process that needs to be discharged
    2.        Leachate drains are generally required to prevent the build-up of moisture in the base of the composting chambers.
    3.        Will manage moisture when systems are subject to over use
    4.        Is a code requirement

    Organic carbon materials

    1.        Compost would not be composting without the compositions of nitrogen and carbon
    2.        Carbon materials feed the composting process
    3.        Provide a bulking bed for waste (human dejecta) to break down in
    4.        Is a wicking bed for moisture to spread evenly
    5.        Will allow the dejecta to fully break down resulting in rich organic soil in a timely fashion

    Human dejecta (waste-not)

    1.        Human dejecta being poos (faecal matter) and wees (urine) is necessary to feed the composting process
    2.        Poos provide to the composting process the base stock for biological life not only giving nitrogen but introducing bacteria to the process
    3.        Wees provide more nitrogen and maintain the moisture in proportion to the amounts of poos and carbon materials added, preventing the composting from becoming too dry

    There are a few more consideration to the effectiveness of composting and these are if it’s a heated system and the climatic conditions the system is used in. These are addressed in the manuals and troubleshooting below.


    Brief Troubleshooting FAQ’s covered here.

    See system manuals for comprehensive Trouble shooting guides (Link) 


    Why is the compost chamber filling up too quickly?

    This can be caused by ineffective composting process due to a number of issues listed below:

    Compost pile being too wet

    This means liquid is trapped in the compost chamber contributing to quick volume build up.

    Check if the drainage outlet is being blocked, this could be caused by solids blocking the drainage system. See respective manuals for information on how to clean drain systems.

    If drainage outlet is ok, consider below factors.

    Insufficient air flow

    Without sufficient air flow, the evaporation process will be slowed and odours start to escape into the toilet room. A malfunctioning fan or ventilation system can cause this.

    Has the ventilation been blocked by dust, insects, bulking materials or toilet paper?

    The fan might not be running, check the electrical connections.


    Climate – Temperature & atmosphere conditions

    WCTNZ make every attempt to match you with the right system meeting your site and climate conditions but there can be changes in weather patterns that lead to less than ideal situations.

    In the colder climate, systems can slow down in their rate of processing. Depending of the type of system you have this may not be a problem.

    In wetter or salt laden air climates the system may retain too much moisture as salt works as a wetting agent by holding on to moisture like water crystals.  

    Over use

    Although most composting systems have an allowed over-use capacity for guest, there can be unexpected additional users that push the system beyond its limits.


    Why is the composting process slow to complete?

    Composting process is dependent on temperature and humidity. Listed below are factors that could slow down the process:

    Compost pile being too wet

    The addition of wood shavings is an imperative part of the operation of a composting toilet. Wood shavings will assist with the absorption of liquid in your composting toilet and will aid in improving the carbon/nitrogen ratio (important for composting) and will allow air to move more freely through the system as it loosens the compost pile.

    Compost pile surrounding temperature is too low

    You can..

    Turn up the heat if your system is a heated model.

    Turn down the fan voltage to lessen cool air being drawn into the system. If odour occurs due to the fan voltage being turned down low simply turn it up slightly to increase airflow.

    Add insulation to the tank, but not if it’s in a sunny location where the heat is warming the tank.

    For two stage systems where secondary treatment is required, when taking the compost chamber out for secondary composting, make sure it is located in a warm spot - preferably in direct sunlight.

    How to deal with insects attracted to compost pile?

    Usually insects in the compost pile indicates that the humus is too dry. Add a cup of water to the compost.

    Insect Control

    To break the breeding cycle of insects (most commonly vinegar flies) spray the compost pile with pyrethrum based insect spray for 7 consecutive days. Always place a layer of wood shavings over the top of the pile in the out of service chamber to eliminate the possibility of insects laying eggs.


    Clivus Multrum – Troubleshooting Guide

    The following Guide is available in full from in the official Clivus Multrum Owner’s Manual.

    For your convenience, it is available here in detail if your manual is no longer available. To download your system manual please login to see your system and corresponding documents.


    Odour present in the toilet room

    A properly functioning Clivus Multrum system does not produce odours in the toilet room. Occasionally, however, the draft of the system may become impaired or a leak may develop in a chute or a vent resulting in odour.

    Note: You should never use a room exhaust fan where a Clivus is installed as the exhaust fan will draw up any odour from the toilet chute (particularly if the toilet seat is not closed). The fan in the toilet vent pipe will be sufficient to draw any lingering odour out of the toilet room.

    Recommended course of action:

    • Check that the power source is connected and voltage is set to 12V, and that power point is switched on
    • Check that ventilation fan is operating correctly and that vent pipe is free of blockages or dense cobwebs.
    • Ensure that the fan has been installed so as to draw air up from the bottom of the vent, not blow downwards.
    • Check that fan is not obstructed from turning by dust or cobwebs. Clean if necessary and replace into housing.
    • Check that open windows and doors are not ‘sucking’ air out of the toilet room due to outside air turbulence. This can overpower the suction of the vent fan.


    An odour is present outside the building but not inside

    Some odour from the top of the vent pipe may occur, but it will rarely, if ever, be detected at ground level.

    This is obviously not a desired occurrence.

    Recommended Course of action:

    • Ensure that the vent pipe is installed correctly and that it clears the roof by at least 0.6m.
    • If the house is in a very windy area you could be getting a swirling effect which is pushing the ventilation gases back down towards the ground. In this case, the only thing that can be done is to extend the vent pipe into clear air flow above the highest point of the roof.
    • If the vent is in the wind shadow of nearby trees or buildings, then odour may settle back to ground instead of being dispersed. Extend the vent pipe into clear air flow.
    • Check that all joins in the vent pipe are sealed and are not leaking. Also check for cracks in the vent pipe and seal with silicone sealant and duct tape.
    • A strong unpleasant odour is a sign the composting process is not operating in balance. This usually indicates the bulking material should be added more frequently or in greater quantities. Check the state of the compost pile and refer below for any corrections.


    Odour is associated with the end-product

    In a properly functioning system the final composted material should be virtually odourless, much like garden soil. However, if proper ventilation and oxygen are not provided during the composting process the pile may have become anaerobic.

    Recommended course of action:

    • Check that vent fan is operating properly and ensure there is no significant build-up of liquid in the removal area.
    • Shovel material from the removal area back in through the inspection door adding a substantial quantity of wood shavings and mixing through with the maintenance tool.
    • Increase the quantity of wood shavings that are regularly added after each use.


    Fan is making a lot of noise

    Recommended course of action:

    • Check fan for obstructions - has it been correctly installed in the fan housing and is not rattling.
    • Lower the transformer voltage to 7 or 8 volts.
    • The fan may be faulty, phone Clivus for a replacement.


    Some liquid present in removal access area of composting chamber

    With periods of very high use, especially when accompanied by low outside temperatures you may get a little liquid build up in the access area. However, if there is more than just a few centimetres and there is odour present …

    Recommended course of action:

    • Ensure that sufficient wood shavings and/or other organic bulking material has been added to the system according to the operation and maintenance instructions. If not…
    • Add several full buckets through the inspection door and toss through the top 30cm of the composting pile.
    • Ensure that adequate quantities of wood shavings are regularly added to the system.
    • Check that the liquid drain is clear from obstruction and has been correctly installed so as to slope away from the chamber.


    A significant liquid build up in the tank has occurred

    Most likely the Drain Line has become blocked.

    Recommended course of action:

    • Check the tank outlet fitting is not blocked by any solids or plastics.
    • Check the liquid drain and absorption trench are clear and not damaged, or affected by ground water.
    • If liquid is non-offensive and a clear ‘tea’ colour, drain off excess liquid and dispose according to local requirements.
    • If liquid is more than 10cm deep, has an offensive odour or is contaminated with solids or scum, this indicates the lower part of the compost pile has become anaerobic (no oxygen). This situation is best remedied by emptying the tank and then restarting the composting process as described in the Operations Manual. Septic tank clean-out contractors can readily pump out the tank and dispose of the contents.


    Compost tank is getting too full

    Factors to consider:

    • Is the pile too dry, too wet or too cold? (Refer below).
    • Is the unit being overused, particularly in cooler months?
    • Is the composting process active (Refer below)?


    The composting process does not seem to be working

    Note: the top part of the pile will not be composted unless it has had sufficient residence time in the tank.

    It is normal not to notice any composting for the first six months.

    Recommended course of action:

    • Check that the suitable bulking agent is being used.
    • Check that disinfectant or antibacterial cleaners are not being used in the pedestal.
    • Is the pile too dry, too wet or too cold? (Refer below).
    • Adding a couple of buckets of damp decaying leaf litter and soil found naturally under trees or material from another compost pile will ensure that the correct microorganisms are present to break down the waste. 


    Composting pile appears too dry

    In normal circumstances there will be sufficient moisture entering the toilet to ensure adequate moisture levels. If however, there have been extended periods of little or no use or where outside temperatures have been very high, it may be necessary to periodically spray the pile with water via the inspection door.

    Recommended course of action:

    • Use the maintenance tool to agitate as much of the compost pile as possible and moisten lightly via the inspection door.
    • Note: Pile should be made damp NOT sodden. Optimum moisture content is around 50%.


    Compost pile appears too wet

    Pile should be damp NOT sodden. Optimum moisture content is around 50%. Too wet is a sign that insufficient wood shavings are being added to the pile and/or that the toilet has received heavy use and insufficient maintenance.

    Recommended course of action:

    • Add several buckets of dry bulking material (wood shavings in particular) through the inspection door and agitate thoroughly through the pile.
    • Increase the quantity of wood shavings added regularly.
    • Check the vent fan is operating correctly and vent pipe is clear of obstructions.


    There seems to be too much toilet paper visible on the top of the pile

    Ensure sufficient bulking agents are being added regularly (per use).

    Consider that some people use much more toilet paper than is necessary.

    Recommended course of action:

    • Simply dampen down if necessary and agitate top 100mm or so of the compost pile to mix with the wood shavings.
    • Check that the composting system is not too hot and dry as the moisture will break apart the toilet paper.
    • Consider the type of toilet paper used. Recycled toilet paper breaks down the fastest and hypoallergenic toilet paper has less chemicals that could resist the composting process but in general this is not a problem.  


    Composting pile may be too cold for composting

    If the compost tank has been correctly sized for the usage and climate, this problem will rectify itself in the summer. Clivus Multrum systems operate successfully in very cold climates if properly sized and maintained.

    If the tank is in a cold location and is becoming full without sufficient composting occurring, the following measures can increase the rate of decomposition.

    Recommended course of action:

    • Insulate the tank from a concrete floor.
    • Insulate the sides and top of the tank to retain heat in the compost tank.
    • Reduce the airflow through the inlet grill at the front of the tank, or duct it to draw air from a warmer location.
    • If tank is in a cellar, duct warmer air into the cellar.
    • Introduce earthworms into the compost. A local worm farm or nursery can advise on a suitable variety for the conditions.


    Undesirable insects in the compost tank

    If insects have gotten into the compost one should sprinkle either Insect stopper or any other long lasting powder (pyrethrum based) over the compost and also in the compost removal tray.

    Refer to section on Compost Toilets and Insects in the Manual.