Where Is The Sail Switch on an RV Furnace?

Having a propane furnace on your RV is an amazing thing to have. This fantastic provider of heat also brings some potential risks. That’s why there are two safety measures. 

The sail switch is the first important switch for safety, and the second one is the high limit switch. That’s why it’s important to know the location of these switches.

In today’s article, we will elaborate on where is the sail switch on an RV furnace and a few sail switch-related topics.

What Does A Sail Switch Do On An Rv Furnace?

A flow switch, van switch, or sail switch is a mechanical switch that turns on or off in reciprocation to water and air-like fluid. It basically prevents the furnace from igniting in case the blower fan doesn’t function properly.

If the blower fan spins at a proper speed, the furnace will ignite. The speed of the blower fan can be detected by a sail switch. When the sail switch senses the blower fan is not moving air properly, it won’t let the furnace ignite. So you won’t be getting heat, but that is a good thing.

The furnace needs to go through two basic proofs to ignite. One is to prove the sail switch is made, and the second one is the high limit thermostat has not been tripped. 

You may face problems like your fan is blowing, but there is no ignition. Then you have to check if the above two proofs are made or not.

If the sail switch does not make a connection, the heater believes there is not enough airflow, and if it ignites, it will cause a fire. To avoid fire blowing cold air flow is crucial. It is a safety measure.

Any issue with the blower fan or fan not sipping at proper speed will cause the sail switch not to connect. It may happen if the blower motor doesn’t get enough battery power/charge.

A Sail Switch Do On An Rv Furnace

It can happen if the house battery of your RV has a low charge.

This sail switch, not the connecting problem, may also happen because of dirt. Dirt or ash may clog the sail switch and make it unable to connect.

To make sure the sail switch is working, you can perform an rv furnace sail switch test. In this test, you will use a multimeter to check if the resistance between two terminals is high when the switch is closed and low when switched on or not.

If you want to light hydro flame rv furnace, turn the gas valve on to pilot position and light it using a match. Wait for a moment to let the gas flame burn, and then turn the gas valve to on position.

Where Is The Sail Switch On An Rv Furnace?

First, you have to take the cover off the furnace. To do that, you will need to remove four screws. After taking the cover off, you will see the inside of the furnace. 

You will see an exhaust tube that vents out any gas created from the combustion process, propane that generates heat, wiring, a circuit board, and a sail switch.

And you will find a sail switch on the duct, right where the gas valve of the burner overrides. It should be attached with a single screw and two sets of wiring. The sail switch is an easy component to locate as it is on the right front side.

See the rv furnace wiring diagram below to understand better.

RV Furnace

On suburban sf rv furnace, sail switch location is external. The sail switch is outside of the squirrel cage cover, and the sail is inside the cover.

Every furnace has a sail switch. There is a sail switch for dometic rv furnace too.

If you have an entrance board for your RV’s heater that provides access externally, you can fix, clean, or even replace the sail switch from the outside cover of your RV.

You will find the second most important switch for safety measures, the high limit switch near the sail switch.

However, on the Atwood furnace, it’s a bit different. The atwood 8535 sail switch location is inside the plastic fan cover. To get to the sail switch will need to remove the blower first.

Atwood 8531 iv dclp sail switch location is on top of the fan housing, which is on the back of the furnace.

And if you want to test the atwood 7916 ii limit switch, you will need a multimeter and a heat source. A properly working limit switch should be around 170° Fahrenheit.  

Can I bypass the sail switch on my RV furnace?

A sail switch is a mechanical switch that works as a safety measure and nothing else. So, yes, you can bypass the sail switch on your RV furnace. But we highly recommend not to do that.

The sail switch protects your RV by preventing the furnace from igniting when the blower fan is not working correctly. If ignition happens when the fan is not working as it supposes to, then the fire may break out. This fire may seriously damage your RV and any person inside the RV. That is why we don’t recommend bypassing the sail switch on the RV.

To bypass the sail switch, you can disconnect the wire connecting to it. On dometic furnace sail switch location would be upright, and on Atwood, it would be inside the plastic fan cover.

Can I bypass the sail switch on my RV furnace

Having a problem with the sail switch should not be a reason to bypass it. If you have any dometic sail switch problems, just call domestic customer support at 800-544-4881 and tell them the furnace serial number and the issue you are facing with the sail switch. They will send you a replacement sail switch free of cost.

If you notice any bad sail switch symptoms, either fix it or replace it. A bad sail switch shouldn’t be the reason for bypassing it.

What does sail switch closed mean?

The sail switch closed means it’s connected, and then the firing cycle starts. And after some time, it returns to its normal position to start the cycle again.

If there is an issue within the blower fan, the sail switch will not close.

What does sail switch closed mean


We believe, after reading through this article, you are now aware of where is the sail switch on an rv furnace, its functionality, how to bypass it and if you should bypass it just because you could or not. 

Making sure you have a functioning sail switch is crucial. Without out sail switch providing a connection, the furnace won’t ignite. That is why it is important to know the sail switch’s location in case you need to fix it for yourself.

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