Suburban SF30q quit during the night

[RAINEYTXX]

Full timers and our primary furnace quit overnight-fan will not run. Power to furnace, can hear click on control board when turning on but no fan. Power from thermostat into blue wires for heater but no fan.

Control board? Does the furnace slide easily out of it's sleeve or is there ductwork to disconnect?

Cold weather coming and want to get running asap. The control is in the rear of the enclosure so gas line and electrical connections have to be disconnected. Is there power and ground and blue thermostat wire only? Gas connection easy to connect/reconnect with no leaks. Plumbed with solid copper line but has 90 degree elbow at furnace with threaded connection.

Thoughts or suggestions of other things to check.

[KJINTF]

Chris and Doug

I sure appreciate your comments/suggestions
You are two of the very few folks that know how to get things done
Please keep your comments coming

Was kind of hoping to obtain a used "defective" control board to repair and have a spare. Seen so many folks purchase a new "Board" when most of the time a < $5.00 part will fix what ever is wrong on most any circuit board (Yes TV boards, Inverters, Converters, etc....). O' well after all it's a throw away society toss it in the trash and purchase a new one - all will be good

[dougrainer]

Chris Bryant wrote:
It could have also been a stuck sail switch- the new fan control boards will not start the blower if the sail switch is closed without the blower running. The original board may well be OK.

Good catch. Doug
PS. The OP is a warranty clerk for a RV dealership.

[Chris_Bryant]

It could have also been a stuck sail switch- the new fan control boards will not start the blower if the sail switch is closed without the blower running. The original board may well be OK.

[RAINEYTXX]

NinerBikes wrote:
Did your board cook because of low voltage and high amperage?

Board was not "cooked" as I could see no burn marks. Voltage steady at 13.1 as we have P.D. Converter and maintains very steady voltage all the time. This is a very low use furnace 300 hrs maybe 3 years old.

[NinerBikes]

Did your board cook because of low voltage and high amperage?

[dougrainer]

RAINEYTXX wrote:
Changed the board and hi-limit switch (switch was good, but since I pulled the furnace, might as well for a $5.00 part) and we have ignition!

Glad to be toasty. Had plenty of wire to pull out without disconnecting wires too. DRV thought of everything!

Main control board has fan relay built in to the board. The Hi limit will NOT stop the motor from running but will stop the Ignition sequence. Doug

[RAINEYTXX]

Changed the board and hi-limit switch (switch was good, but since I pulled the furnace, might as well for a $5.00 part) and we have ignition!

Glad to be toasty. Had plenty of wire to pull out without disconnecting wires too. DRV thought of everything!

[enblethen]

There should be a small circuit breaker that has a reset button.
Yes, it could be a bad motor, time delay relay or circuit board.
This may help
Manual

[RAINEYTXX]

Grandpere wrote:
Bad fan motor. Sail switch will not close without the fan running so propane will not ignite.

MMMM, maybe...no prior issues however. Spins freely, no squealing or fan slow-downs prior but a guess it could be possible.

[RAINEYTXX]

Johno02 wrote:
Propane level.

Propane level won't cause furnace fan not to come on rather it will come on then quit-the other furnace we have works fine. Propane full.

13.4 volts, too.


Thank you though...

[Grandpere]

Bad fan motor. Sail switch will not close without the fan running so propane will not ignite.

[Johno02]

Propane level.