# More Furnace Problems



## samvalaw (Feb 17, 2005)

I have tried all the fixes mentioned here, none work. The FAN does not even come on in furnace mode. When turning the unit on in Fan mode only, the fan blows air. If I switch it to furnace mode, the fan stops and I hear nothing...
This happened once before and I tightened down the connection in the fuse panel and it worked. Now, that fix doesn't get results....
Any thoughts?


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## Hokie (Jul 10, 2006)

I'm not sure what other fixes you have tried since they are not in this thread. Here is my assessment given the limited information:

1) The fan running in "fan" mode is a good thing, that means at least the fan circuit to the furnace is working.
2) I am certain in "furn" mode, you have the temperature on the thermostat cranked all the way up, right?
3) What connection to the fuse panel did you tighten?
4) I don't have the furnace schematic in front of me, but that is where I would go next to see what signals the furnace needs to start running and then check them. I can try to look for that tonight if no one else provides you with any more suggestions today.

Good Luck,
Sam


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## Guest (Nov 6, 2006)

Steve,
I dont know if our systems are different, but in "Fan" mode my unit runs the fan in the overhead unit. The biggest difference in the air conditioning and heating functions are that the air conditioner/fan, except for the control circuitry, are A/C and the heating unit is DC. You might want to take a second look at the DC side of the house. Low battery, converter/battery charger problems and blown fuses could all give the symptoms that you are descibing. Hopefully it's something simple.

Happy camping,
Gary


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## Moosegut (Sep 24, 2005)

Sensai said:


> Steve,
> I dont know if our systems are different, but in "Fan" mode my unit runs the fan in the overhead unit. The biggest difference in the air conditioning and heating functions are that the air conditioner/fan, except for the control circuitry, are A/C and the heating unit is DC. You might want to take a second look at the DC side of the house. Low battery, converter/battery charger problems and blown fuses could all give the symptoms that you are descibing. Hopefully it's something simple.
> 
> Happy camping,
> Gary


Ditto. Fan mode should only work for the air conditioner. Low battery could be a big culprit here. The circuit board and spark igniter need enough power to work. And the fan needs battery power too. In my old TT when the battery was low, the fan would run but it would not ignite. I was surprised to find that the igniter and circuit board needed more juice than the fan. Also, check all connections - wires, clips etc. Sometimes, just pulling a clip connector off and putting it back on is enough to establish a contact that might have become oxidized.


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## PDX_Doug (Nov 16, 2004)

samvalaw,

I think the others are on the right track here. I would check all connections on the 12V side, and make sure you have sufficient voltage to the system. Also, make sure your propane system is in order, tanks are full and valves opened. If that does not turn anything up, and you are still under warranty, this may be a good time to call the dealer.

Good luck!

Happy Trails,
Doug


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## samvalaw (Feb 17, 2005)

Thanks for the replies:
The temperature guage is cranked all the way up. I have tried it at several temperatures.
I tightened the wire behind the furnace breaker.
I am not very handy, so reading the schematic won't do me much good...
The unit is on shore power and I believe (but not sure) that both propane tanks are about half full. Wouldn't the fan come on regardless?
What do I look for when trouble shooting the 12v side?
I am not under warranty.
The other fixes included looking for spiders/webs, resetting remote, running propane stove prior to turning on...


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## Oregon_Camper (Sep 13, 2004)

PDX_Doug said:


> samvalaw,
> 
> I think the others are on the right track here. I would check all connections on the 12V side, and make sure you have sufficient voltage to the system. Also, make sure your propane system is in order, tanks are full and valves opened. If that does not turn anything up, and you are still under warranty, this may be a good time to call the dealer.
> 
> Doug


Cost me $75 for the Mobile RV guy to show up at my house and tell me my connections were not proper...which of course kept my heater from coming on as it would not get the required power and the circuit board would just shut off the system.


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## Thor (Apr 7, 2004)

I agree with the others. Check the 12v supply. Shore power, fuses, loose wires?

Good Luck

Thor


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## CamperAndy (Aug 26, 2004)

bentpixel said:


> I feel your pain.
> 
> 
> 
> ...


The emergency button is a place to start for making sure the system works but even it will not work if it is too warn in the trailer, unless you use it in test mode (see below near the bottom). Also your starting sequence is wrong. The fan in the furnace comes on before the ignition or gas and purges the firebox and establishes air flow, then igniter and then the gas.

This all could be due to a faulty control board but I would try starting from scratch.

Replace the batteries in the remote and press the reset button on the back of the remote. Then turn off the remote until you are ready to test the system.

Disconnect the trailer from shore power and disconnect the batteries. Once fully powered down, pull down the cover on the AC unit to expose the control board for the remote. Check all the wires for a good connection. Leave the cover off.

Re connect the trailer battery, re connect to shore power if available. Now turn on the remote and stand with it pointed at the AC unit change the modes of operation until it indicates Furn. You should heat the AC unit respond with a beep as you make changes. Set the temperature up and then WAIT a minute. There can be delays in operation when you first turn on the AC or furnace. The Furnace will only come on if the setting in the remote is higher then the temperature in the trailer. If it does not respond to the remote and it is too warm (above 73 deg F) then the emergency button will not work.

So you need to use the Emergency button in test mode. To turn on the furnace in test mode, push and hold the emergency button for at least 5 seconds. It should over ride the temperature control and start the furnace.

Let us know how all this works.


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