Furnace won't stay lit

Blower comes on.....flame lights then goes out.

Spark electrode is what lights main flame.......it is also used to prove that main flame lit. (milivot signal generated by main flame...goes back to circuit board so DC power stays on gas valve holding it open)
If electrode is carboned up, not engulfed in main flame or ceramic is cracked -------no signal/gas valve closes.

bid_time wrote:
It's basically the same as the thermocouple on your water heater. Look for an electrode above where the flame would be on your furnace.

This above, I also make sure my exhaust port is clear with compressed air and if I don't have fully charged batteries or plugged into shore power, my furnace doesn't operate very well at all.

CLEAN CLEAN

It's basically the same as the thermocouple on your water heater. Look for an electrode above where the flame would be on your furnace.

What's a flame proofer

Clean the flame proofer.

Yes to #1 will get info.

I'm posting for my sister. From what I gather when she turns it on the blower kicks on then the furnace lites, then shuts off.

1. Is your propane full, and have you bled the air out of the system. Turn on several burners on the top of your stove and make sure that you have good flames.

2. Provide the manufacturer name of your furnace so the knowledgeable folks on here can help you.

Too little information to offer suggestions