Furnace won't ignite

[cdru]

The furnace on our travel trailer won' ignite. The fan comes on, but the furnace itself does not ignite. It is a forced air type with floor vents and a wall thermostat. I pulled the outside cover and noticed a little red light blinking. Any ideas??????? Thanks

[westend]

cdru wrote:
It seems now that the temperatures have warmed up out of the 20's and 30's, the heater seems to be working again. Today was in the mid 40's and it worked fine. Does that indicate low pressure in the propane line?? Thanks

It's probably not a pressure problem, there is a very forgiving pressure that the gas is delivered to your furnace, 11" of water column or about 1/2 psi. For those theorizing that cold temperature caused the problem, come fishing with me some time in the Winter. We routinely keep a 20 lb. canister on the ice to heat the fish house at temps well below zero.

If I was to offer a diagnosis, it would be that the furnace failed to ignite the first three tries and went into lockdown. That could relate to a gas line that was not purged of air. Another cause could be a faulty thermostat or dirty electrical connections. If you do have dirty or oxidized connectors, any drop in 12 V power source will exacerbate the problem.

Good luck with the furnace!

[fdwt994]

This link may explain what happened:

[Bisker]

cdru wrote:
It seems now that the temperatures have warmed up out of the 20's and 30's, the heater seems to be working again. Today was in the mid 40's and it worked fine. Does that indicate low pressure in the propane line?? Thanks

I have the same problem, when it gets cold my furnace wont light, must be government issue, only works when you don't need it.

[cdru]

It seems now that the temperatures have warmed up out of the 20's and 30's, the heater seems to be working again. Today was in the mid 40's and it worked fine. Does that indicate low pressure in the propane line?? Thanks

[johnnyrv]

Does your stove light all burners? If not the check valve in the lp tank pigtail could be defective. That happened to me and is a cheap fix to replace the pigtail.

[punomatic]

I once had this problem, and the culprit was about a cup of bees and other dead insects in the combustion chamber. Cleaned 'em out and she fired right off.

[TKW]

The furnace circuit board on my last trailer only lasted 2 seasons. It cost about $300 for the parts. Hope it's not the case for you.

[cdru]

Thanks for the information.....

[Old-Biscuit]

Caveman Charlie wrote:
It means that the furnace tried to light 3 times and when it didn't it shut down as a safety feature.

Correct....
Which means main flame didn't light

Could be as simple as dirty connections, dirty gas orifice, dirty burner, dirty spark electrode, spark electrode gap OR failed gas valve, bad spark electrode/wire, bad circuit on control board.

Remove outside access panel
Remove connectors on board...clean contacts on board with pencil eraser and check that pins on connector are making good contact when connector is plugged onto board.

Then try furnace.

If it still doesn't light off you will need to pull burner assembly/spark electrode and clean.
Clean up electrode with 400 grit sandpaper and set gap to 1/8"
Clean/inspect burner.....rust/debris obstructing gas flow
Unscrew orifice and clean with alcohol

Reassemble and test furnace.

[Caveman_Charlie]

It means that the furnace tried to light 3 times and when it didn't it shut down as a safety feature.

[cdru]

It was the # 4. Three flashes at a time. So what does that mean?? Plenty of propane as both tanks are full and the stove and oven both work.

[xteacher]

Check to make sure you don't have a faulty regulator on the propane tank. If that's okay, try lighting your stove top burners (all of them), to get the air out of the lines. We used to have to do that to get our oven to light.

[uintafly]

Also check your battery levels (assuming you are not connected to shore power). In my old trailer if my batteries started getting close to 50% I didn't have enough juice for the igniter to kick on. If you are connected to power, obviously it wouldn't matter.

[Old-Biscuit]

The 'little red light' blinking is a 'fault' light.
How many times/how fast it blinks indicates what the error is.

Fault Codes:
1. Internal Circuit Board Failure (Steady on, no flashing)
2. Limit switch/Airflow problems (1 flash with 3-second pause)
3. Flame Sense Fault (2 flashes with 3-second pause)
4. Ignition Lockout Fault (3 flashes with 3-second pause)

SO.....which one is 'problem'?