Furnace won’t light

[Kwralph]

Everything works except furnace. It won’t ignite.
I put fan on auto and then go to furnace, nothing happens. Set fan to hi or low they come on but not furnace . Propane’s good in both tanks .un hooked both tanks re hooked one at a time. Nothing . Tried both open nothing from furnace . What next ??
Oh it a surban .
Thanks

[Scrapper]

The furnace is 12vdc powered so check the furnace fuse in your power center / breaker box / fuse panel. If the fuse is good check that your battery(ies) are fully charged.

You say when "Set fan to hi or low they come on", do you mean the furnace fan or air conditioner fan?

When you set the thermostat to auto and set it to heat do you hear the furnace blower start then clicking from the furnace a couple seconds later?

If you post the make / model of your furnace and either a picture of your thermostat or the thermostats make / model you will get help specific to that setup.

[Chuck_S]

I suspect you're playing with the air conditioner. Set the thermostat to HEAT. Furnace fan (singular) is automatic when furnace heats up. The FAN control on my thermostat controls the air conditioner unit on the roof, not the furnace which blows out heat at floor level thru separate ducts.

Does your LP stove work? No flame there means no gas in system.

-- Chuck

[Kwralph]

Model of furnace is SF- 42Q
Fuse check out good by eye. I didn’t probably test with tester plus I’m not able to tell which is furnace . But I suspect fuse is good ...maybe not.
I now suspect the Fan I’m hearing is the AC fan sense it’s blowing out the ceiling.
I have set fan to auto.set thermostat to furnace raised temp up to different degrees alway to 90 . Nothing. No sound of any kind . I did find a switch inside of outside furnace cover that was a on and off . It was set to on . I cycled it a few times and set back to on just as it was . Nothing.
I’m going to test all 12 volt fuses with tester next.
Fuse tested good. Stove and hot water heater work.
Thermostat is a dometic.
I see someone posted that they reset furnace? How is that done ??

[Scrapper]

My comments are in blue.

Originally Posted by Kwralph

Model of furnace is SF- 42Q
Fuse check out good by eye. I didn’t probably test with tester plus I’m not able to tell which is furnace . But I suspect fuse is good ...maybe not.

Sometimes just by looking can fool you into thinking the fuse is good, if you have a multimeter set it to the dcv setting and hold one test probe to the ground bar in the power center, touch the other probe to one leg of the fuse then move it to the other fuse leg. If the voltage reading is the same on both fuse legs then it is good, if different the fuse is blown.

I now suspect the Fan I’m hearing is the AC fan sense it’s blowing out the ceiling.

The AC blows from the ceiling, the furnace blows from floor or vents low on a cabinet or wall.

I have set fan to auto.set thermostat to furnace raised temp up to different degrees alway to 90 . Nothing. No sound of any kind . I did find a switch inside of outside furnace cover that was a on and off . It was set to on . I cycled it a few times and set back to on just as it was . Nothing.

The furnace does not have an outside access panel, what you describe is the water heater outside access panel. The switch you describe turns the WH electric element on/off.

I’m going to test all 12 volt fuses with tester next.
Fuse tested good. Stove and hot water heater work.
Thermostat is a dometic.
I see someone posted that they reset furnace? How is that done

To reset the furnace when it goes into lockout just turn the thermostat heat switch to off then back on.

Do you not have the operation installation manual for your furnace? The reset procedure is outlined in the manual.

??

The outside intake/exhaust panel will look like the attached picture.
Also attached is the owner manual and service manual for your furnace. Be forewarned, the service manual covers every forced-air furnace Suburban makes.

Thermostats are generally covered in the AC manual or sometimes a separate operation pamphlet.