Lighting furnace pilot

jimsaxman · 01-08-2014, 03:03 PM

Sorry to bring such an elemental question to this forum, but since it is a dangerous subject, I think I had better ask. My furnace has gone out. Ran out of propane, when I refilled the LP the furnace won't go back on. Air in the line is my guess. I look at the furnace housing and there is no flame. There is no igniter button, no pilot/run knob on this 2004 Georgetown. What should I know before I stick a spark in that gap?

fonzie · 01-08-2014, 03:13 PM

Light up your burners on your stove to make sure you are getting gas and to purge the lines. Once the line is purged then try your furnace again. It might take a few tries before it goes. Hope it works.

jimsaxman · 01-08-2014, 03:24 PM

Thank you for that. We have lit the burners on the stove several times, but I have seen no flame at the furnace. Is this something (the furnace pilot) that Is supposed to be lit?

fonzie · 01-08-2014, 03:33 PM

Normally furnaces of this vintage would be DSI (direct spark ignition) meaning there is no pilot light. When thermostat is turned up, it will send signal to furnace control board to start the furnace blower, if blower is OK, a sail switch will close and tell control board to apply voltage to dsi electrode and open gas valve at same time. Furnace should light up and dsi spark stops. If you know what model and make of furnace you have then post it so people can help with more diagnostics.

Dave_Monica · 01-08-2014, 03:52 PM

You may still have air in the propane line to the furnace. I'm pretty sure that the furnace would be direct spark. You turn on the furnace at the thermostat, if it fails to light, turn the thermostat off once the fan's stopped...repeat this process as times as needed until the air is completely gone from the propane line and the furnace lights.

Dave

alparmer · 01-08-2014, 04:58 PM

We completely ran out of gas also and it took a while for it to come back on. I just left the thermostat on and it did it automatically. I'm guessing once the air purged out.

**wmtire** · 01-08-2014, 05:29 PM

If you have a Suburban furnace, Page 3 of the following troubleshooting document in our library may help in the understanding of how the furnace works, and how it locks itself out after 3 failed attempts to light.

Forest River Forums - Downloads - Furnace - Suburban furnace troubleshooting

petey · 01-09-2014, 01:24 AM

Quote:

Originally Posted by wmtire

If you have a Suburban furnace, Page 3 of the following troubleshooting document in our library may help in the understanding of how the furnace works, and how it locks itself out after 3 failed attempts to light.

Forest River Forums - Downloads - Furnace - Suburban furnace troubleshooting

just what alparmmer said leave it on until air is gone in line. This will do it. starting stove top will help this, what most people do is wrong not leave it lit on stove long enough. Pete

jimsaxman · 01-09-2014, 05:16 PM

Thank you all for your help. Unfortunately, I have been unable to re-ignite this thing. For what it's worth, I did crawl around and find the make and model. Its a Suburban model SF-35F. Vintage about 2004 I imagine. It does seem to have direct spark ignition, but it won't spark up.

fonzie · 01-09-2014, 05:53 PM

When you set your thermostat for heat, does the furnace blower start?

jimsaxman · 01-09-2014, 07:35 PM

Yes, the blower goes on for about 30 secs. then shuts off. No heat during that time.

jojo bamboo · 01-09-2014, 09:03 PM

you should hear it sparking at the same time
tick, tick, tick, tick, tick, then stop and then start again.
until the furnace fires

jimsaxman · 01-09-2014, 09:28 PM

So I understand. No such thing happens. Do I have a fuse problem? I've checked the fuses in the house and battery compartment, but I haven't checked those in the "power distribution center". Maybe that's next? Also, I can't find a sail switch. Maybe someone with this furnace (Suburban SF-35F) could help me locate it.

JohnandPandra · 01-09-2014, 10:03 PM

Are you sure your not in lock-out mode on your furnace. It will try 3 times and if no flame, then go into the lock-out. Try turning your furnace to the off position, then try again.

jimsaxman · 01-09-2014, 10:48 PM

How do I do that? You mean a switch on the furnace itself? I saw a video of such a switch on utube, but I haven't seen it on my furnace. I'll look. Thanks.

JohnandPandra · 01-09-2014, 10:59 PM

On your thermostat.

jimsaxman · 01-10-2014, 12:05 AM

Oh yes, I've done that. Many times. Still no clicking sound. I'm going to look for a fuse problem tomorrow. Too late tonight. Thanks.

fonzie · 01-10-2014, 05:35 AM

Here is service manual for your unit if you don't have it already.

**KyDan** · 01-10-2014, 07:28 AM

You say the furnace fan will run for 30 seconds then stop.
You don't hear the tic tic tic of the spark.
This sounds to me like the sail switch is not closing.
That's a switch that's blown shut by the force of the blower.
The sail switch must close before the gas valve will open.
I'm not sure if the sail switch must close before the igniter sparks
but I want to say it should close first.
If the blower comes on but the sail switch does not close, nothing else
will happen.

You're getting pretty close to needing to pull out the furnace for further
testing.
This isn't typically that hard to do but if you're not electrically inclined it
might be time to call a repair man.

jimsaxman · 01-10-2014, 04:23 PM

Yep. I'm beginning to see the picture. The repairman will be here tomorrow morning. Thanks to all for your help.

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