What is the 12 Volt Fan?

The 12 Volt Fan is meant 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 evaporative performance of your non-electric unit by about 10 to 15% (still not enough to evaporate all liquids on an NE).

Its purchase is optional with an Excel NE, a Centrex 2000 NE, or a Centrex 1000 NE.

In Which Situations would I need a 12 Volt Fan?

  • 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.
In Which Situations Would Sun-Mar recommend a 12 Volt Fan?
  • If the unit is being used residentially
  • If you expect heavy seasonal use

In Which Situations Would Sun-Mar Not Recommend a 12 Volt Fan?

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.

If you live in a coastal area that is rich in salt air - you may want to consider purchasing a more expensive, but more durable fan from Nicro; these fans are used in marine applications and may be purchased from marine supply stores. Our fans will stand up to most weather conditions, but do not do well in salt air.

Which units come with the 12 Volt Fan?

Excel AC/DC 1.9 Watt 12 Volt Fan
Centrex 2000 AF NE 2.4 Watt 12 Volt Fan
Centrex 2000 AF AC/DC 2.4 Watt 12 Volt Fan
Centrex 3000 AF NE 2.4 Watt 12 Volt Fan
Centrex 3000 NE 2.4 Watt 12 Volt Fan
Centrex 3000 AF AC/DC 2.4 Watt 12 Volt Fan
Centrex 3000 AC/DC 2.4 Watt 12 Volt Fan
Centrex 2000 AC/DC 1.9 Watt 12 Volt Fan
Centrex 1000 AC/DC 1.9 Watt 12 Volt Fan

Is Installation of the 12 Volt Fan required on the above models?

AF (Air Flow) NE 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 models:
Installation of the 12 Volt Fan is only required on these models where both vent stacks have been installed, or any of the other situations exist where Sun-Mar recommends its installation.

Centrex 3000 NE:
While installation of the vent fan is not required on this model, it is highly recommended for assistance with airflow, or any of the other situations exist where Sun-Mar recommends its installation.

How Do I Install the 12 Volt Fan?

Choose a section of your vent where you will easily be able to access the fan, and connect it to the battery. Cut a suitably sized section of vent stack 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). Caulk both seams with silicone for the best airflow.

Why can't I just use a computer fan?

Our fans are protected from moisture and weather, except in the case of air that is rich in salt (see above). While they may look like computer fans, they aren't.

How Do I Power the Fan?
With DC Power:
Purchase a solar panel appropriate to the wattage of your fan (5 Watt for the 1.9 watt fan, 10 watts or above for the 2.4 watt fan). You will also require a 12 Volt battery (Sun-Mar suggests a deep cycle marine battery for best results). Connect the wires on the fan (red wire positive, blue negative) to the appropriate terminals on the battery, and the appropriate wires on the solar panel to the battery. The battery will store the charge from the solar panel, ensuring continuous operation of the fan even at night or cloudy days.

With AC Power:
Purchase a 12 Volt AC Adapter from any electronics store. Cut off the female plug. Attach the positive wire to the red wire, the negative wire to the blue wire, and secure both with small wire connectors (marrettes). Plug into wall.

What Different Voltages and Watts are these fans Available In?

12 Volt 1.9 Watt Fan
This is the fan which is shipped when you order a 12 Volt Fan. It will do for most situations, and has the lowest draw.

12 Volt 2.4 Watt Fan
This fan increases the airflow level and is necessary for situations where there may be competing drafts, which is true in the case of the AF NE models and the AC/DC, dual-vented models.

24 Volt 3.3 Watt Fan
For those with 24 Volt systems.


12 Volt Fan Installed In Vent Stack

12 Volt Fan - Red Wire Positive, Blue Wire Negative
Interior View of the 12 Volt Fan