Atwood furnace

H. Dossett · 03-11-2007, 03:12 PM

I have an '01 National RV with an Atwood furnace problem. Fan comes on, I can hear the click of the igniter, and I can smell a small amount of propane at the exhaust. Clicks about every 15 to 20 seconds. Just no flame. Pulled the unit out, and with no propane going to it, I could see the spark. The spark looked weak to me, but I have nothing to judge that by. I checked the gas pressure by lighting all three burners on the stove and that looked good. The problem started after I set up and used the furnace a couple of mornings, then switched over to a portable tank, then flew back east for a few days. Margaret called and said the furnace didn't work. Luckely, it warmed up in Tucson and was out of heat only one morning when it was needed.

Any suggestions, comments, or leading questions?
Thanks for any help.

Harold

H. Dossett · 03-11-2007, 03:12 PM

I have an '01 National RV with an Atwood furnace problem. Fan comes on, I can hear the click of the igniter, and I can smell a small amount of propane at the exhaust. Clicks about every 15 to 20 seconds. Just no flame. Pulled the unit out, and with no propane going to it, I could see the spark. The spark looked weak to me, but I have nothing to judge that by. I checked the gas pressure by lighting all three burners on the stove and that looked good. The problem started after I set up and used the furnace a couple of mornings, then switched over to a portable tank, then flew back east for a few days. Margaret called and said the furnace didn't work. Luckely, it warmed up in Tucson and was out of heat only one morning when it was needed.

Any suggestions, comments, or leading questions?
Thanks for any help.

Harold

"007" · 03-11-2007, 04:45 PM

H. Dossett welcome to the forum

When you switched over to the portable the line to the furnace may have air in it and needs to be cleared. Stove may work but line to furnace still has air in it.
If you keep trying to light it it may clear after a few trys.

Enjoy the forums and post often.

RV Wizard · 03-12-2007, 12:32 AM

Harold, welcome to iarv2.com. We are glad to have you join us here. Have you gotten the furnace retarted? You may want to try it off the main tank and if it works from there check the fittings and valve on the portable tank feeding the system. GOod luck and keep us posted.

H. Dossett · 03-12-2007, 08:02 AM

A little more info:

The furnace worked for two or three days after I switched to the portable tank.

I have ordered the RV Repair and maintenance manual. After 5 years on the road, I need it more and more!

What should the Electrode to ground gap be. It did not look fouled up or anything and the burner looks clean enough. The gap is about 3/16".

What are the chances of the control board being bad with the symtoms listed?

RV Wizard · 03-12-2007, 08:44 AM

The gap is right at 3/16". One thing you will want to be sure to check is that the burner is clean and especially at where the electrode is. Also check to be sure the gas fuel pressure is 11" water colum. Be sure the blower wheels and vents are clean and no pest have built a nest in them. If you have a volt meter or 12 test probe be sure you are getting good 12 (13 volt) at the gas valve and control board. The gas valve will only be opened for a short time while the igniter starts sparking. Let us know what you find.

H. Dossett · 03-13-2007, 02:44 AM

Hi again.

Another update on the furnace.

Pulled out the control board this morning and dusted it off with a small paint brush. (had to act like I was doing something useful.) Put it back in and turned it on and lo and behold, it fired up. Fast and loud, 'bout had a heart attack, standing next to it with the cover off. Ran the thermostat down and it turned off just like it should. Could not get it to relight after that.

Any suggestions?

Harold

RV Wizard · 03-13-2007, 11:32 PM

Harold, Do you have and know how to use a multimeter? The unit needs to be properly diagnosed as we can only guess and offer things to check. According to Dinasour, 80% of board problems were loose conections. Have you checked the gas pressure with a monometer? I would start there just to be sure it is right; if so then make sure the igniter is sparking and at the same time the gas valve opens after the unit has gone through about a 7 second purge period. Good luck and let us know what you find by continuing this topic on the RV Syatems and Appliance section down the main page of the forum.