Furnace refuses to start up

[STANG23L]

Now that fall weather is here. Attempted to use the furnace for the first time last weekend on my Cherokee 274vfk. Looks like an owners manual for the furnace was never provided just the thermostat. So was up the creek with out a paddle. Luckily I brought an electric heater with so we survived the 50 degree nights.

Setting the thermostat to auto fan mode then setting the temp 68-70 on heat mode. It attempts to fire for 30-60 seconds then shuts down.

If I set the fan mode to low/high the furnace does nothing and the a/c kicks on. I do not believe the a/c in my 274vfk has a heat strip. So this also baffles me.

Any ideas what it could be?

[larry_cad]

A frequent problem with the furnace is a corroded ground wire connection on the furnace. Find the wire that is fastened to the metal part of the furnace with a screw, remove the screw, clean both the metal surface, and the wire connected to that point. The ground wire is a functioning connection, not just there for safety. Also worth unpluging the circuit board from the flat connector, and cleaning those flat connections with a pencil eraser.

[enblethen]

Sounds like a dirty sail switch.
Blow furnace out good with compressed air.
Make and model of furnace?

[STANG23L]

wnjj wrote:
First of all the fan switch is only for the A/C unit and does nothing for the heater.

If the heater fan runs for when you turn the heat on but doesn’t light, it’s either not getting propane, the igniter is bad the sail switch (which detects the fan running) is bad or the control board itself failed (less likely). Before all of that, is your battery fully charged or are you plugged into shore power (I assume so since you ran a space heater)? If the fan doesn’t run fast enough it will not attempt to light.

Also try lighting a stove burner first to be sure you have propane flowing and the most air purged that you can.

Is this a brand new unit or new to you?

To answer the basics. We were connected to 30amp service. We fully used the stove/oven, pilot was lit entire weekend. Furnace is under the stove so it should be getting propane.

The fan does kick on for the 30-60 seconds with airflow out the floor ducts and furnace exhaust.

[wnjj]

First of all the fan switch is only for the A/C unit and does nothing for the heater.

If the heater fan runs for when you turn the heat on but doesn’t light, it’s either not getting propane, the igniter is bad the sail switch (which detects the fan running) is bad or the control board itself failed (less likely). Before all of that, is your battery fully charged or are you plugged into shore power (I assume so since you ran a space heater)? If the fan doesn’t run fast enough it will not attempt to light.

Also try lighting a stove burner first to be sure you have propane flowing and the most air purged that you can.

Is this a brand new unit or new to you?