Furnace won't power on

[ratowles]

I have a 2010 Keystone Cougar Xlite 27RLS. The furnace won't power on. The fan does not come on and it does not attempt to light the burner. I have checked all of the fuses and breakers and wiring and all looks good. I suspect the wall thermostat unit, mostly because there are two identical units from the previous owner, which are marked bad. All other functions work; fan and cool. Just have the issue with the furnace setting.

It is a Suburban furnace with a Domestic thermostat.

Any ideas?

[chuckster57]

Brand of furnace and thermostats?

[ratowles]

Suburban furnace with Domestic thermostat.

[ErickW]

Originally Posted by ratowles

I have a 2010 Keystone Cougar Xlite 27RLS. The furnace won't power on. The fan does not come on and it does not attempt to light the burner. I have checked all of the fuses and breakers and wiring and all looks good. I suspect the wall thermostat unit, mostly because there are two identical units from the previous owner, which are marked bad. All other functions work; fan and cool. Just have the issue with the furnace setting.

It is a Suburban furnace with a Domestic thermostat.

Any ideas?

I have been having the same problem the past few days, hopefully someone can help us, otherwise I think I will just have to replace the damn thing.

[ratowles]

RV Doctor came out and found a loose connection of a wire up in the air conditioner compartment. Solved the problem.

[ratowles]

The furnace runs reliably during the day. However, once the sun goes down and the outside temperature drops, the furnace will fall to cycle and then will not come back on until you reset the thermostat. At that point it becomes hit or.miss on whether the furnace operates and even if it does come back on, once it reaches temperature and cycles off it rarely will cycle back on. RV Doctor coming back out tomorrow to take another look.

[nitrohorse]

I'd be curious to find out what loose wire the tech found on the AC unit that prevented the heater from working. They are two separate units independent of each other. Without being able to hang my VOM on it, I would look at the thermostat as the culprit.

[ratowles]

I was not here when they found the loose connection. I plan on having them show me what they did when they get her today. Stay tuned.

[ratowles]

First I have attached pictures of the connection which was disconnected. It is the wire connection on the top of the grey box. Turns out the furnace and the air conditioner are powered from a central box.

Lastly, the furnace is now fixed. It turned out the AC to DC Converter/Charger board was bad and was not consistently providing the required voltage to the furnace. The symptoms which finally caused us to look at the Converter was the fact the batteries were not staying charged, the DC lights were dim and the furnace fan was not turning at the proper speed. If the furnace does not get a minimum of 10.5 volts the gas valve will not open and the furnace will not light when trying to cycle back on.

Anyway, problem appears to be fixed now. I will run a test overnight and report back it problem recurs.