Burner and Blower Won't Start For Furnace

[heyhello]

Hey guys,

my dad was trying to fix the furnace because its not working and won't produce heat. I looked up briefly on the net to find a solution to this and found one method on here by a fella named 'lewster'. He suggested that the thing you should check up first is the t-stat, where you open it up and connect two wires and wait a few seconds to see if the furnace starts up again. My dad tried this and nothing happened.

What could be the problem? Any suggestions and helpful things we could do would be appreciated. thanks.

I'll provide some info if need be.

[Alumaholic]

Like what is the year and make of the Airstream?
Is it Suburban furnace?
What is the ignition method?
Have you checked the sail switch?

[saburkha]

i'm having similar issues with my 1976 suburban furnace. I can get the pilot to light and stay on, but nothing happens when i adjust the thermostat. No blower, no burner. Not sure if I should be looking at a thermostat problem or elsewhere. That may be where i start first before attempting to get into the guts of the furnace. Any help would be appreciated.

[eubank]

I agree with Ken: We need more info about what heater you're talking about and the exact symptoms.

In general, I've found quite a few problems with sail switches. In our model, when the sail switch fails, the fan will start up, but there's no propane flow, and the ignitor will not work. Remove the sail switch, clean it up (or replace it), and the heater works fine.


Lynn

Originally Posted by Alumaholic

Like what is the year and make of the Airstream?
Is it Suburban furnace?
What is the ignition method?
Have you checked the sail switch?

[dcheshire]

Hi, I've read several of the threads on this issue and would like advice on the order I should check things.

I have a 1973 Ambassador with the suburban furnace (pilot light, not circuit board).

Furnace worked fine last season, this season, went to use it and experienced the following.

1. turned on gas valve under sink that supplies furnace
2. open view window an lit pilot. pilot stays burning
3. close view windows and inspection cover that you have to open to see the light

all of the above is exactly as I've done it every year (this is our 3rd year with the trailer).

4. crank up thermostat... NOTHING happens
5. recheck that pilot is still going, yes it is.

I have jumpered the thermostat, thinking that maybe that would do it, but that didn't work.

I have checked the main fuse in the converter fuse block for the furnace and it's fine.

What can I check next before calling a mobile rv repair guy out to fix it. (it's in my driveway now, so easy for me to try a couple of easy things.

Any help would be appreciated. thanks!

[mayco]

The blower should immediately kick on when the thermostat calls for heat. Are you plugged into shore power? Batteries fully charged? Inadequate voltage to the unit will cause the blower not to function properly. Ou must have proper blower speed to activate the sail switch which activates the gas valve. Im guessing low voltage, bad connection to furnace (check with meter at furnace), or blower motor kicked the bucket

[cwf]

Folks.. Check age of thread. It is pretty old...

[mayco]

I saw that, looked to me like they were searching through old threads to find something that related to their situation. Dunno.

[mayco]

Their post was from 4:43 pm today

[cwf]

My mistake, Mayco... please forgive.

[mayco]

No biggie

[dcheshire]

Hi folks. Sorry for resurrecting an old thread. My hope was to not go over the things already covered in the previous thread. So I've got a pilot going, and I've "short circuited" the thermostat and I've checked the one fuse I know about (unless there are secret inline fuses somewhere).

So now it sounds like
1. check voltage at thermostat?
2. check voltage somewhere in the furnace?

[dcheshire]

Originally Posted by mayco

The blower should immediately kick on when the thermostat calls for heat. Are you plugged into shore power? Batteries fully charged? Inadequate voltage to the unit will cause the blower not to function properly. Ou must have proper blower speed to activate the sail switch which activates the gas valve. Im guessing low voltage, bad connection to furnace (check with meter at furnace), or blower motor kicked the bucket

Hi, to answer this. This happened when on shore power (13.X volts in the system from PD9245 converter) and when just on a fully charged batter (all lights/etc are bright, no reason to think voltage is low).

[dcheshire]

Checking further, there is no voltage at the thermostat. Is there an inline fuse between main fuse box and the furnace?

[mayco]

Only the hot 12volt leg goes to the thermostat so if you checked for 12volts there I assume you found a ground. No voltage at the thermostat would mean a bad connection at the furnace (typically the 2 blue wires I believe), a bad wire going to the thermostat, or could be circuit board related. Check the easiest first, connections at the funace. Never heard of an inline fuse to the thermostat but you never know what people may do.....highly doubt it though. Did you check the voltage, incoming TO the furnace. Check that first.