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Furnace problem

Yahoo Message Number: 9562
Hello All,

Our '99 Allure has the standard gas fired furnace. A couple of weeks ago I could not get the furnace to light and checked the fuse in the panel that is ;ocated in the by with the filter and battery cut-off switches. Replaced the burned out fuse but the furnace fan still does not come on. Any suggestions-- did I miss any fuses anywhere else.

Thanks in advance
Egon

'99 Allure

Re: Furnace problem

Reply #1 –
Yahoo Message Number: 9564
I've not had "the opportunity" to trouble shoot one of these, but I think the first thing after the fuse might be to see if you can detect or hear any ignition of the igniter trying to strike a spark for ignition. (I assume its the electronic spark type and not the "match" type.) Secondly, can you detect any gas flowing; probably by smell and possibly sound. The book says furnaces fail to perform if system voltage is lower than 10.5V. Batteries fully charged? Check the gap on the spark igniter...it should be about 1/8". There may be an excessive amount of air in the system if the coach has been in storage. Try lighting the cook top first to get rid of most of the air. Check the orifice on the end of the gas supply line. Put some soapy water on the orifice and push the pilot-light button. If no bubbles appear.....have a clogged orifice. If that's the case, probably have to replace the orifice as cleaning is pretty tricky in that small, soft metal hole. Another remote thought is the sail switch. I looks just like a micro switch with a longer handle-type lever that actuates the switches contacts. It's located in the air plenum and detects whether there is adequate air flow for proper combustion. If there isn't, (say there is low battery voltage and the fan won't produce enough pressure, or there's some sort of obstruction) the sail switch will prevent the gas control valve from opening. Does the fan operate?

Quote from: cctravelingman

Re: Furnace problem

Reply #2 –
Yahoo Message Number: 9567
The fan should come on first and run for just a little while and then the furnace should light but the fan does not even come on.
I have taken the wood grill off the kitchen cabinet to acess the furnace but it is toatally enclosed and I can't get to any of the working parts-- ignitor etc.

Thanks,
Egon

'99 Allure

Re: Furnace problem

Reply #3 –
Yahoo Message Number: 9571
Quote from: cctravelingman
>

Replaced the burned out fuse but the furnace fan > still does not come on.
In most cases, fuses do not fail of their own accord. There is a reason ..... more current than the fuse is rated ..... which causes fuses to blow. Sometimes the higher than designed current is momentary but sufficient to blow the fuse, sometimes it is permanent... e.g. a short circuit that does not clear. Because you say this fuse is in the fan circuit, and the fan does not run..... I would suspect the fan motor having an internal short. You don't say whether this fan runs on 12VDC or 110VAC.

If it were mine, and I could easily access the fan, I would try disconnecting the fan and powering it from the appropriate voltage source, protected by same or slightly higher rated fuse, to see if fan runs. Check first for obvious stuff like chaffed wires, seized bearings, plugged fan etc. Then do electrical test BUT ONLY IF YOU KNOW WHAT YOU ARE DOING, if not, get help.

Joe

2004 Allure #31031
Florida

Re: Furnace problem

Reply #4 –
Yahoo Message Number: 9574
Joe,

The Fan is on a 12v circuit but am not sure if the fuse that was blown is on the fan circuit or some relay or something. Just wondering if there was another fuse for the fan motor tha I have not found.
Egon

'99 Allure

Re: Furnace problem

Reply #5 –
Yahoo Message Number: 9576
Quote from: cctravelingman
>

Hello All,

Our '99 Allure has the standard gas fired furnace. A couple of > weeks ago I could not get the furnace to light and checked the fuse > in the panel that is ;ocated in the by with the filter and battery > cut-off switches. Replaced the burned out fuse but the furnace fan > still does not come on. Any suggestions-- did I miss any fuses > anywhere else.

Thanks in advance

Egon

'99 Allure

Hi Egon,

I had problems with my furnace that was similar to your description.
The solution to get my furnace working again was to clean it. Dust and lint built up on the fly switch. It would not allow the blower to run before the furnace would ignite. Take the wood grill off at the furnace and run a vaccum cleaner over the entire area. This got my furnace working initially. Mine quit again at a later date. I eventually removed the furnace (not an easy task) to remove the furnace housing and get to the fly switch. If you do this, I think you will find a lot of lint and dust around it. Once I cleaned it and reinstalled the furnace, it worked like a new unit.

Dave G.

2000 Allure #30491
Millheim, Pa
 

Re: Furnace problem

Reply #6 –
Yahoo Message Number: 9584
I'm with Joe; you have to test the fan motor by disconnecting it from its source wiring and hooking a hot 12V and ground directly to the motor leads to see if it runs. Doesn't really matter which lead goes to what; if backwards, the motor will just run backwards, but the test is to see if it runs at all. Sure sounds like a fried motor to me.

Quote from: cctravelingman