Furnace blowing cold air

I was having this same issue until I cleaned the end of the propane tube that wraps around the back and into the burner where the solenoid is. The end of that tube has a cap with a pin hole that can unscrew. In my case, the pin hole was plugged with rust particles keeping the propane from flowing through. It was that easy, after much diagnosing the other parts first.

She/He? has a brand new MH, tell her/him to go to Lowes and buy a Stanley squirrel cage ceramic elect. heater. They work great, and heat very well, and get it to a dealer to have it fixed under warranty! And get the screens installed in the outside vents as quickly as possible. She/He may try to run the stove burners and the oven to make sure the lines have been purged of all the air, could just be that,, as the previous poster mentioned! She/He will use the Stanley heater when she/he is plugged in and will love the way it heats!
Hope this helps!

She may not have used it enough yet to get the air out. Have her run the stove for a while and then start the heater. She just may need to purge the lines.

If it's a Suburban furnace, here is some of the fun you can have.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24565501/srt/pa/pging/1/page/1.cfm


If it lights and runs long enough to produce heat, check the solenoid on the fuel valve. How to do it is in the link above.

If on warranty, use an electric heater until you can get it to a dealer.

new unit- have her call the factory warranty department and let them know what is going on- let them know where they will be and see if they can set up something with a repair shop in the area

Old-Biscuit wrote:
Sounds like furnace is starting correctly and lighting main flame but then looses main flame......

Circuit board HAS to receive a 'signal' generated by main flame proving that it is lit. Without that signal.....circuit broad secures dc power to gas valve and lets is close.

Things that cause issue:
Exhaust blocked.......mud dabbers/nests outside vent
Spark electrode not positioned directly over main burner slots where it is engulfed in main flame
Spark electrode ceramic cracked......signal shorts to ground
Dirty/loose/poor connection of spark electrode wire at circuit board
Dirty/loose/poor connection on circuit board multi-wire connector

I'm with Biscuit on this and think that because of the age of the coach, if screens were not installed over the vents daubers have gotten in and built mud nest to restrict air flow. I faught this problem last year in my TT on my deer lease. Finally put screens on. Resolves the problem, but only after furnace is cleaned.

Ya, had a cold front blow through here today-- it is down to 78 degrees.

80 degrees in Central California today. Tell her to head this way and she won't need a heater.

Sounds like furnace is starting correctly and lighting main flame but then looses main flame......

Circuit board HAS to receive a 'signal' generated by main flame proving that it is lit. Without that signal.....circuit broad secures dc power to gas valve and lets is close.

Things that cause issue:
Exhaust blocked.......mud dabbers/nests outside vent
Spark electrode not positioned directly over main burner slots where it is engulfed in main flame
Spark electrode ceramic cracked......signal shorts to ground
Dirty/loose/poor connection of spark electrode wire at circuit board
Dirty/loose/poor connection on circuit board multi-wire connector

First "suspect" is low voltage at the furnace.

Low voltage= slower fan speed= sail switch does not close= fan runs, but ignitor and propane valve don't open.

Of course restrictions in air return or vents will cause the same low air flow and symptoms.