2005 Keystone Furnace Issues

[Robardscampingfamily]

Hello,
I have a 2005 Keystone Springdale with furnace issues. Furnace blower works fine. Furnace will try to ignite and I’ll get about 2 seconds of hot air from the exhaust port. I can hear it clicking. It’s sporadic when it does light, but won’t stay running. I pulled the furnace and didn’t see any debris or obstructions on the sail switch. Any suggestions?

[sourdough]

Others have probably had different experiences but I've had exactly what you describe happen to me twice and both times it was the control board. I guess it could be a faulty thermostat....but, we can see what others have to say.

[ChuckS]

What is the condition of the igniter and gap setting as well as what does the sail switch measure in ohms when you manually move paddle and close switch ?

If it reads much more that 1 ohm of resistance the contacts on that sail switch bars dirty

A good reading would be .05 or less ohms of resistance

[Robardscampingfamily]

Pardon my ignorance, but does the igniter “burn” off and get shorter over time? It appears to be in good shape. I have the furnace out and will probably replace the sail switch and igniter.

[ChuckS]

The igniter ... considering age of your unit has seen some use. The gap may be a bit wide due to normal wear and tear use.

Since you’ve got it out you can verify a lot of things visually such as are the electrical connections to control module board . Sail switch , hi limit switch clean and making good contact?

Also What is the condition of the gas tube orifice jet ? Just saying

[ChuckS]

With ignitor Assy removed look at overall condition and measure gap between the two areas I marked in red. You are Looking for 3/16 measurement

[sourdough]

Originally Posted by ChuckS

With ignitor Assy removed look at overall condition and measure gap between the two areas I marked in red. You are Looking for 3/16 measurement

Chuck, for my own edification, after the furnace ignited and ran long enough to blow out warm air would the ignitor not then be out of the picture?

[ChuckS]

The flame sensor on most Suburbam furnaces is actually the electrode assy which of course is the igniter assy ...

Suburban ....

[ChuckS]

Atwood furnace... the thermocouple on the igniter determines whether or not there is a flame sensed and sends feedback to the control board... if it doesn’t “sense” a flame it shuts off propane solenoid to furnace and locks out

[sourdough]

Thanks. Familiar with Atwood/Dometic stuff but not Suburban.

[ChuckS]

Furnaces can be a pain to TS.... and it would be so much easier if they made the access from the outside. Mine is accessed via basement rear panel door... buried amongst a host of a maze of wires and such...

[Robardscampingfamily]

It appears to have been the sail switch or debris in the oraface, but it’s working fine now. Thanks for all the info and advice!

[chuckster57]

Originally Posted by Robardscampingfamily

It appears to have been the sail switch or debris in the oraface, but it’s working fine now. Thanks for all the info and advice!

The sail switch seems to thrown under the bus a lot. In this case if the sail switch was bad it would never light. There are safeties that have to be met before the control board will allow the gas valve to open and the igniter to spark. I’m glad it’s working now, hope it continues to operate without issues.

[ChuckS]

Totally agree... I wish the OP good luck with this because the sail switch had nothing to do with the issues as he described it...

If sail switch contacts inside switch don’t complete the circuit the igniter will never attempt to fire and there will be no propane flow because solenoid won’t open...