Furnace runs but blows cold

dougrainer wrote:

Teleman wrote:

enblethen wrote:
Can of air with the tube works pretty good!

I got into the blower with compressed air and cleaned all the contacts but it didn't help. I watched this video which explains the procedure for taking the furnace apart to replace the motor, igniter and burner. My motor is good but I'd have to go through all of this to access the sail switch.

https://m.youtube.com/watch?v=oaTW0oNf6Qw

From what I can tell the blue and white wires of the multi pin connector on the board go to and from the sail switch and high level thermostat. Using tap connectors and shorting those wires would get the furnace working IF either the sail switch or high level thermostat were the problem right? If so I know I have to pull the motor to get to them. If not then it could be the igniter or the board. I guess checking the igniter would be the next step.

You do not have to remove the motor to check replace the sail switch. But on a 22 year old Furnace, I would replace BOTH the Sail Switch and the Hi limit switch since they can be intermittant and just messing with a sail switch may make it start working. For a few times. They are cheap so replace both. The Hi Limit can be the cause of your problem. Doug

Are you sure? They are located behind the blower and motor and I don't see how I can get at them with the motor in place. What about my idea of shorting the blue and white wires going to the board to see if the sail switch or hi limit thermostat are in fact the problem? The furnace in the video I linked to is very close to identical to mine.


RV Furnace Motor Squealing - Remove & Replace ... - YouTube

www.youtube.com › watch › v=oaTW0oNf6Qw