Help, Urgent, Furnace no heat

lmacy · 12-22-2018, 10:19 AM

Desperate in PA. We are getting ready to go south for the winter in 5 days, just after Christmas. We had a problem with the furnace not working, so we took it to a shop where the circuit board was replaced. It was working fine and I had the heat set at 42 F. We went out this morning to start the finish packing and the furnace does not deliver heat. I turned the thermostat up to 90 and the fan will come on, but after about 30 sec it stops and no heat is delivered. Sounds to me like the burner is not igniting.

I am starting here to find a solution, guess I could try to get a circuit board from Amazon or someplace. I will be using my friend Google now to find some assistance.

BTW the Furnace is a Suburban SF 30 FQ.

Any ideas??

PS I tried to call the service place, but they are closed on Sat and I actually doubt they will reopen until after the new year. Left a message.

lmacy · 12-22-2018, 10:33 AM

Quote:

Originally Posted by lmacy

Desperate in PA. We are getting ready to go south for the winter in 5 days, just after Christmas. We had a problem with the furnace not working, so we took it to a shop where the circuit board was replaced. It was working fine and I had the heat set at 42 F. We went out this morning to start the finish packing and the furnace does not deliver heat. I turned the thermostat up to 90 and the fan will come on, but after about 30 sec it stops and no heat is delivered. Sounds to me like the burner is not igniting.

I am starting here to find a solution, guess I could try to get a circuit board from Amazon or someplace. I will be using my friend Google now to find some assistance.

BTW the Furnace is a Suburban SF 30 FQ.

Any ideas??

PS I tried to call the service place, but they are closed on Sat and I actually doubt they will reopen until after the new year. Left a message.

New info. I have shutdown all power to the furnace to try to reset the circuit as others have suggested, No joy. Still no heat. Apparently no ignition.

Toddupton · 12-22-2018, 10:41 AM

Are you out of propane?

**Flybob** · 12-22-2018, 10:41 AM

Probably a silly question, but do you have propane?

lmacy · 12-22-2018, 10:43 AM

Quote:

Originally Posted by Toddupton

Are you out of propane?

That was my first thought as it has been sitting for a couple weeks with the furnace running to prevent freezing. Nope, 2/3 tank and the stove works fine.

THanks

Skip12 · 12-22-2018, 10:56 AM

Since you've had it sitting with heat on for multiple days, I doubt this will help, but just in case... Are you on shore power or battery? I've had a similar problem with low battery, presumably because the fan wasn't strong enough to trigger the sail switch.

Also, an electric heater are a good fall back if you're camping with shore power.

lmacy · 12-22-2018, 11:25 AM

Quick answers. Shore power - at home. Tried battery, no joy. Electric is gonna be the way we start, may need to get a "something" or hit a Camping World along the way.

banda · 12-22-2018, 11:25 AM

This site is designed for home furnaces, but they are similar so it might be of some help:
https://www.repairclinic.com/RepairH...rts-then-stops

lmacy · 12-22-2018, 11:27 AM

Any thoughts on maybe calling a HVAC person to assist??

lmacy · 12-22-2018, 11:33 AM

Is this the right board?
https://www.amazon.com/Suburban-SB52.../dp/B00NBPYF7U

Or is this the right Dinosaur board replacement?

https://www.amazon.com/Dinosaur-Elec...J6NFCCVX7PWW0T

ScottBrownstein · 12-22-2018, 11:40 AM

When the burner attempts to light, fails and then shuts down, you have to turn the furnace off and then on to recycle. When you start it if you listen on the outside by the vent you should be able to hear the burner...if you hear it ignite and then goes stop the board is probably the only possible culprit. Hard to work on them since access is limited unless you unscrew the whole thing from the outside and slide it out.

lmacy · 12-22-2018, 11:44 AM

One more bit of info. The fan comes on then stops, I hear no indication that the ignitor is firing at all.

And its a Class C so not issues with bottle switchs

banda · 12-22-2018, 11:46 AM

https://www.rvtravel.com/troubleshoo...nace-problems/

jeff64 · 12-22-2018, 11:49 AM

Quote:

Originally Posted by lmacy

Is this the right board?
https://www.amazon.com/Suburban-SB52.../dp/B00NBPYF7U

Or is this the right Dinosaur board replacement?

https://www.amazon.com/Dinosaur-Elec...J6NFCCVX7PWW0T

Unlikely it's a board since you replaced it...and it was working. Curious as to vintage of camper as to age of components. Cold temps breed propane supply issues. Can you run all 3 burners on your stove simultaneously? Running on 1 30lb tank is a small surface area to vaporize in low temps and maintain required 11 in WC needed for operation of WH furnace and refrigerators. Not quite as significant with stove, that's why 3 burners lit. Regulator?
Check out Warm Guard 20 on amazon. Good luck, my 2 cents worth, happy holidays!

JohnD10 · 12-22-2018, 11:53 AM

I had this issue on my 5'ver...

Turned out to be a wire had come loose (ie.- unplugged) from the circuit board...

A mobile RV tech was doing warranty repairs and when I mentioned this problem he fixed this issue along with the other stuff.

jeff64 · 12-22-2018, 11:54 AM

Quote:

Originally Posted by jeff64

Unlikely it's a board since you replaced it...and it was working. Curious as to vintage of camper as to age of components. Cold temps breed propane supply issues. Can you run all 3 burners on your stove simultaneously? Running on 1 30lb tank is a small surface area to vaporize in low temps and maintain required 11 in WC needed for operation of WH furnace and refrigerators. Not quite as significant with stove, that's why 3 burners lit. Regulator?
Check out Warm Guard 20 on amazon. Good luck, my 2 cents worth, happy holidays!

If you rebooted furnace, you can hear it click and it wants to ignite momentarily ,yes could be board. Could be igniter too. Its ground to chassis quite important.

cavie · 12-22-2018, 01:19 PM

replacing the board is not really a diy project. furnace has to come compleatly out and put onto a bench. and disasembled. You need to plug up the gas line. Remove the 12 volt wiring. Went thru this very thing last summer.

Wilco · 12-22-2018, 02:32 PM

If the burner is not attempting to light, it might be the Sail Switch on the blower. This switch is a little flapper in the air stream the tells the furnace that the blower is running. This switch also give a permissive to light the burner. If this switch does not close, the burner will not light and the furnace will shutdown after a ~30 sec purge.

If the furnace has not run recently, it may take several tries to loosen up the sail switch to allow it to run.

myxkp · 12-22-2018, 03:17 PM

Quote:

Originally Posted by lmacy

Desperate in PA. We are getting ready to go south for the winter in 5 days, just after Christmas. We had a problem with the furnace not working, so we took it to a shop where the circuit board was replaced. It was working fine and I had the heat set at 42 F. We went out this morning to start the finish packing and the furnace does not deliver heat. I turned the thermostat up to 90 and the fan will come on, but after about 30 sec it stops and no heat is delivered. Sounds to me like the burner is not igniting.

I am starting here to find a solution, guess I could try to get a circuit board from Amazon or someplace. I will be using my friend Google now to find some assistance.

BTW the Furnace is a Suburban SF 30 FQ.

Any ideas??

PS I tried to call the service place, but they are closed on Sat and I actually doubt they will reopen until after the new year. Left a message.

Having repaired thousands of residential heaters, stoves, fireplaces etc. I had many cases where someone just changed parts till it would work, never finding the cause. I suggest you rely on your electric heat until you find a reliable repair person.

Brother Les · 12-22-2018, 03:43 PM

Quote:

Originally Posted by lmacy

Quick answers. Shore power - at home. Tried battery, no joy. Electric is gonna be the way we start, may need to get a "something" or hit a Camping World along the way.

What do you mean "tried battery,no joy".

Almost everything will run 12v from the converter with just 'shore power'.... but you should have a good charged battery to run the furnace fan and igniter system for the furnace to run.

Went camping one winter and could not get the furnace to run correctly. All 12v systems 'seemed' to run fine on the camper. Tested the battery and it had a couple of bad cells. Dropped a new charged battery in it and the furnace ran fine. The 'fan' on the furnace was not running steady enough and would not allow the burner to fire.

If you are going 'south', you do not need to run your furnace, get a oscillating space heater and use that on 110 to keep the chill down. We almost never use the furnace, only space heater. Why burn my propane when I am paying for the electric from the box....

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