Suburban gas furnace malfunction question.

[silverkiss37]

Hello,

I have a Suburban furnace. The manual is for models SF-20F thru SF-35F.

So last night I ran the furnace as usual. It started to get really hot in here which was weird so I turned the temp down on the remote that controls the power and temp. It kept running. It was 74° in here and still running! So I turned the power off with the remote and I could see the power went off on the ceiling unit. It did not shut down after a minute like usual. Took about ten minutes before it shut off. Then there was a buzzing sound coming from the ceiling unit and a red blinking light I could see inside. It continued to blink and buzz all night but the buzzing wasn't loud. Kinda sounds like an air pump for a fish tank.

Today I turned the furnace on and it came on but once again it wouldn't stop blowing and it got real hot. So once again I turned it off and it just kept running. I finally had to pull the fuse to make it stop. Which it did instantly. Now if I replace the fuse, it comes right back on altho it's still shut off. The red blinking light and buzzing stop while the furnace is running. It obviously doesn't continue when there's no power to the unit.

The furnace is under my fridge and can be accessed by a panel. But I am not an electrician and don't trust myself to unattached everything. I basically just want to see if anyone thinks this is the sail switch, thermostat, etc... Maybe someone knows what the problem could be? My ex father in law is a really experienced electrician but parts could take months to order so I'm trying to get ahead with an idea. Any help would be appreciated.

Just so everyone is aware, I live in my RV and it's dead winter in the Washington mountains with snow on the ground! Thanks!

[Larry-NC]

The furnace itself is not in the ceiling. It's down low, on the floor, and the heating ducts are either just above or just below the floor.

If you have one of those snazzy new units, it may also have heat from the air conditioner, either resistive heat strips or running the air conditioner "in reverse," as a heat pump, to provide heat. This is suggested by your statement that you heard buzzing from the ceiling.

Did you actually check where the heat was coming from: floor ducts or ceiling ducts? Can you provide the model number of the air conditioner, to see if it has resistive heat strips or a heat pump mode? Can you tell whether the operating noise came from the furnace (grille under the refrigerator)? When the heat is running, can you go outside and CAREFULLY check the exhaust (back-to-back with the furnace inside? It will be REAL HOT if the furnace is running, cool if the heat is coming from the air conditioner.

If you can confirm that the air conditioner does have these features, and the exhaust is cool, this could be operator error--maybe read the manuals REAL CAREFULLY again. Or it could be the thermostat or controls in the air conditioner--beyond my scope.

[5picker]

Welcome to the forum, I see it is your 1st post.

You say it is dead winter where you live.
Did you ever run the furnace previously?
Did it work OK or is this the 1st time you have ever turned it on?