Suburban SF-30FQ furnace will not run. Thermostat works, power to unit OK. Can even hear switch click when call for heat, but now blower, no action.

SOURCE: furnace problem

The problem is most likely in the control module of the roof air unit. Dometic uses the thermostat to activate and deactivate a relay in the control board of the roof ac unit whiich is just visible when you remove your air intake screen. The two blue with white stripe wires are the furnace control wires.

The furnace turns on and off by the opening and closing of relay. Most likely, the furnace control relay is stuck in the on position. On the thermostate, remove the fur wire and see if the furnace quits afrer it cycles down...it does not quit right away. With the termostat out of the loop, if the furnace does not shut down, the problem is in the control box. They are not hard to replace but you must be careful with the live wiire from the 110 ciucuit breaker. If you are not comfortable with the repair, take it to a dealer. The part number is on the assembly box. They need to know if you have the heat srip option or whatever othert options our Roof AC has. If the furnace still runs with the blue/white wires disconnected, the furnace wires are shorted somewhere between the furnace and the AC control unit.

SOURCE: ATWOOD MOBILE FURNACE RUNS WHEN IT WANTS/

Check your furnace for power. will be 4 wires. power ground and 2 thermostat wires. Check for power at the time delay relay, if you have power there check for power going in the fan motor, if power in motor wire, motor is bad. If no power in motor wire and power going to circuit board take the 2 thermostat wire apart and wrap the 2 together comimg from the thermostat. Fan will stat in about 30 seconds. If it does you need a control kit in the ac. But sounds to me like you have a furnace problem.

Mike Butler

• 6674 Answers
• Posted on Jul 08, 2009

SOURCE: I have a DuoTherm BriskAIr 13.5K BTU. The Dometic

If you look at control box at roof unit, they usually use a separate set of wires for furnace. See what colors they are attached to at harness to thermostat. Some just follow other harness, and come out at thermostat. (bypass control box) Once you've determined which 2 they are, join them together & see if furnace starts, as it should. If it does, thermostat is faulty. If not, pull outside cover off & check voltages at furnace. I'm guessing by furnace model that your unit is approx 30 ft , but if it's a park model, you may have 24 volt system on furnace or 12 volt. Another way of confirming is to go to back of furnace where air intake grille is inside your unit, and locate 2 blue wires going to furnace & remove whatever wires are attached to them & connect them together. Furnace should start up.

Testimonial: "thanks for the link. info solved my problem."

SOURCE: I have a suburban lp furnace and duotherm air/heat

I'm not sure what the problem may be but you could try calling All Seasons RV Appliance Parts & Service. There number is 1-800-344-0673 they have helped me in the past. That and there tech calls are free so it wouldn't hurt to give them a call.

SOURCE: furnace will not start. a/c seems to work ok. i

ok don't go off the last guys answer.. ur heater runs through the ac unit but is a 12 volt issue. check your fuses at the board. if not that then your heater ignitor board needs to be replaced... or it has a fail switch on the heater...