Furnace help please!!

[crazyzoe]

I have a Suburban NT20S furnace. When I turn the thermostat on the blower fires up and then the furnace makes a click sound and I can hear the burners fire up but they won't stay going to produce heat. It will do this three times before having to turn off and back on and goes through this again. I can see some exhaust steam come out of outside exhaust port. Any ideas what might be causing the burners to not stay going?

[ikatcher]

probably a dirty flame sensor. should be a thin metal rod that sits near the burners. when flames are on this should be in the flame. clean the rod with steel wool. (not sandpaper)

[FWR]

I had the very same issue last week with my Atwood forced air furnace. I switched from 20lb tanks to 30lb tanks and it now lights and runs with no issues.

[harvey lee]

Could be a bad sail switch also. If the fan does not blow hard enough, the sail switch could be bouncing on and off of the sail switch and that could shut the furnace on and of.

I have a heater that was giving me nightmares. It would turn the fan on, burner would lite and run for approx 15 seconds and then cut out. Bit later, rerun the same cycle.

We took the furmace out, check gas pressure, limit switch, sail switch, checked for 12v of power and all was good.

Then we pulled the ignitor out and one could see what looked like hard mud packed inside the area by the ignitor. Pulled the igniter out and cleaned out all the mud.

Mud Dauber's got in there last summer and made one heck of a mess.

The guy that I purchased the house from said the heater worked fine last year and here we are, but finally working.

I will be putting a mud dauber screen in before this summer.

I believe we had checked everything on the furnace before we took the ignitor out and saw what we did. One never knows.

[bigtimeelectric]

I had a similar issue last week. I always carry a hair dryer in my pick up for frozen locks and such. I took it and heated up the regulator on my lp tank and tried it again and now works fine.

[crazyzoe]

I have it hooked up to 30 pound tanks and have tested the regulator and checked a few other things. I tried again tonight firing it up and when the burner fires up it will make a loud "poof" sound sometimes. I noticed when I started to take it apart that part of the gasket was missing where the burner inserts in. Could this be causing the problem? If so anybody know what I could use to fix gasket or where to find one?

[hawgchaser]

It's a ceramic fiber gasket that you'll probably have to get online or from the company. I forget the product name but you can get sheets of it that you cut to fit. I went to 4 HVAC places this fall looking for a sheet, but none of them had it in stock. I think a search for combustion chamber gasket or furnace gasket would lead you to what you're looking for. I'll probably wake up in the middle of the night and remember the product name.

[crazyzoe]

Thanks....thinking that is the problem. Not sealed up tight. I wonder if you could use like a high temp automotive gasket and cut to size.

[hawgchaser]

I think they're only good to 500 degrees intermittent. I was rebuilding my Paulin Pup heater and ended up buying a medium thickness fireplace door gasket. I undid the braiding and used one of the strands for the gasket, but that's a 9000 BTU open flame heater. For a furnace, I'd want the real thing to seal it off. I bet if you saw it ignite in the dark, you'd see a flame flash where your gasket is missing. Be safe first...creative second.

[crazyzoe]

I found the replacement gasket online for $7.67 so I ordered it and got the next day shipping so hopefully it is here on Saturday!!

[harvey lee]

You should be good to go.

[IcePro]

I would check the gas orifice.

This could be plugged partial and not allowing the gas to flow freely. The orifice is smaller than a pin and it does not take much t plug them.