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Robert
Robert, RV Mechanic
Category: RV
Satisfied Customers: 12178
Experience:  18 yrs. RV experience including Cummins North West, Country Coach, Monaco Coach - vendor certified.
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Im trying to figure out why my furnace stopped throwing

Customer Question

im trying to figure out why my furnace stopped throwing heat.
Submitted: 1 year ago.
Category: RV
Expert:  Robert replied 1 year ago.

Hi my name is Robert..

The first thing to do is to see if the unit is sparking or not. Click HERE for a service manual on this and it will tell you what to look at. It is going to be a process of elimination to see which component is causing the issue. Might be hard for you to check the gas pressure but it really should be verified IF the heater is sparking. As soon as you turn the thermostat on and set the temp the blower fan should come on once the signal goes through the limit and sail switch you should get spark and the gas valve should open up. The manual should help out. IF you have more questions or concerns please feel free to contact me, follow ups are included... Robert

Customer: replied 1 year ago.
I had the pressure checked and it is fine, when I turn on and set the thermostat there is a few sec delay and the blower motor comes on but there is no ignition spark.
Expert:  Robert replied 1 year ago.

OK

You are going to have to check for continuity through the sail switch and limit switch. As the blower motor comes up to speed it will close the sail switch, if the sail switch does not close you will never have spark. Check your voltage as well, if the voltage was even a bit low the fan would still run but not be enough to close the sail switch. So that is what I would look at first, look at the manual I sent it should help. IF you still need more help please let me know, getting ready to go out on a service call so I will responded if needed when I get back... Robert

Customer: replied 1 year ago.
Thank you Robert, I'll have to figure out where the sail switch is. hopefully this will fix the problem.
Customer: replied 1 year ago.
sorry Robert but that didn't fix the problem.
Expert:  Robert replied 1 year ago.

OK

I am back sorry about that...... Did you check continuity through the sail switch and limit switch, when the paddle is closed you should have continuity.

No worries on going back and forth.... Follow ups are included..... Robert

Expert:  Robert replied 1 year ago.

It is sounding to me like the board is bad if you have continuity through the sail and limit switch. Most RV shops have the ability to check the boards with a special tester. You should be able to get a board through Dinosaur Electronics, they are well known in the RV world and make a great product and have great support. Click HERE for the contact info. If the fan is good and you have voltage through the sail and limit I would change the board. IF you would like to try another expert please let me know, my goal is for you to be satisfied with my efforts, I only get credit when you select a rating...

also click HERE for some more info on the board.....

Expert:  Robert replied 1 year ago.

Just checking in to see if my answer helped, IF you have more questions or concerns please feel free to contact me...

Robert