Vent Installation

Similar to conventional toilets, one of the main tasks is the installation of the vent stack, which is required with all units.

The vent kits included with each toilet are sufficient for installation in most single story buildings. If more is needed, they are normally easy to find. For electric units, the vent pipes used are 2″ thin wall PVC* and can be obtained by special order through most builder supply stores, or from Sun-Mar directly. 

For non-electric units, the vent pipe used is 4″ ABS pipe and can be purchased from most builder supply stores. 

*Please note that 2” thin wall PVC is not the same diameter as 2” PVC pipe, and that the two cannot be interchanged when installing a Sun-Mar toilet. Doing so may result in odor in the proposed installation location.

Vent pipe can be installed up the inside wall and out through the roof, or through the wall at no less than a 45° 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. 

All connectors in the vent pipe nearest to the toilet should be sealed with a thin bead of regular grade silicone, in case the toilet has to be moved or you have to access the built-in fan. For all portions of vent that are exposed to the elements, PVC cement may be used if desired. All exposed vent pipe should be insulated against the cold, to prevent freezing and blockages in the pipe. This is especially important for winter or residential use. The type of insulation varies based on location and installation, however at the very least, using wrap around plumbing pipe insulation on exposed pipe is recommended.

For installation information that is specific to your unit, consult your owner’s manual, or call our customer service department at 1 888 341 0782 ext 218 if you have any questions. 

Vent pipe can be installed up the inside wall and through the roof, or through the wall at a 45° angle and up the outside wall (with this configuration, a 12 volt fan is necessary). 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 pipe should be installed as near to vertical as possible. This is necessary because a non-electric toilet functions with passive venting, and any bends in the pipe could lead to odors if installed without a 12 volt, in-line fan. Silicone caulking should be used for the connection of the vent stack to the toilet because at some time the toilet may have to be moved, or you may wish to install a 12 volt fan in the vent stack in future. Any exterior connectors should be sealed with PVC cement.

For installation information specific to your unit, consult your owner’s manual, or call our customer service department at 1 888 341 0782 ext 218 if you have any questions. 

For questions on the 12 volt fan, please see the section below, titled, ‘The 12 Volt Fan’. 

(All Units Except Sun-Mar Mobile)

The diffuser provided with the toilet is a simple device to be installed at the top of the vent stack with the larger pipe protruding above the smaller. The diffuser design encourages updraft, and discourages wind and weather from going down the vent stack. Unlike wind turbines, diffusers are less likely to freeze up in winter, and are more effective in calm weather. 

The Sun-Mar Mobile units are not furnished with a diffusor, and an appropriate vent cap must be purchased by the owner for these toilets.

The vent stack should end about 24-30 inches above the highest peak of the highest roof so that it is less subject to downdraft. Where the vent pipe is taken through the roof, an appropriate roof flashing may be required to seal the installation.

If you have a Sun-Mar Mobile unit, you may terminate the vent stack above the deck/roof with an appropriate vent cap. 

The 12 volt fan is designed to accelerate airflow in all non-electric units. It comes pre-installed in an 11″ piece of 4″ diameter vent pipe so that it will fit inline in your vent stack. It also protects against downdraft and increases the evaporation performance of your non-electric unit.

If you have to put any bends in the vent stack (Sun-Mar recommends no more than two 45° elbows, even with a 12 volt fan installed) if your cottage is subject to downdraft. A fan us also recommended if the Non-Electric is being used residentially, or if you expect heavy seasonal use.

If you cannot run the fan continuously, it will act as a blockage in the vent stack. If you need to get around this, you can install it in a “bypass vent” off of the main stack.

A/F (Air Flow) non-electric toilet models:

These models require the installation of the 12 Volt fan to ensure that air is being drawn down the Sun-Mar dry toilet in the bathroom.

AC/DC converted models:

Installation of the 12 volt fan is only required on these models where both vent stacks have been installed.

CENTREX 3000 NE:

Based on the size and volume of the Centrex 3000 NE, it is highly recommended for assistance with airflow.

Choose a section of your vent stack where you will easily be able to access the fan, and connect it to a battery or power source. Cut a suitably sized section of your existing vent pipe and insert the fan into the stack, ensuring that the piece is positioned correctly so that the fan is blowing upwards (coupling will be at the bottom). Use silicone caulking to seal both seams for the best airflow.