[hanadul]

I inspected the furnace and found it starts normally (frame, main blower, another motor on top of furnace... etc.) initial time but main blower stopped after 2 -3 minutes even though frame (fire) is on. Frame went out 1-2 minutes after main blower stopped. Frame is continuing to on and off but main blower never starts again except first time. First time means shut down the main switch, wait 5 minutes and bring it back on.

Main switch down---wait 5 minutes---main switch on---furnace starts normally (frame, main blower, motor on top of furnace)---main blower stopped in 2 minutes(fire is still on and top motor is running)---frame(fire) stopped(top motor still on)---frame(fire) turn on with top motor but no main blower---frame(fire) is continue to on and off and top motor is continue to run but main blower is continue to down.

What I did so far,
Cleaned air filter.
Cleaedn main blower motor housing & inside of furnase.
Replaced capacitor (7.5 uf 370v)

[hanadul]

My main description was a little ugly.

Let me explain again.


Main blower on my furnace has stopped in 2-3 minutes and never come back.

Here's steps
1) turn the thermostat up
2) inducer motor switches on, and comes up to speed
3) the pressure switch detects that the correct negative pressure has been reached and turns on the hot surface ignitor
4) the hot surface ignitor heats up and gets white hot
5) the main burner gas switches on and the burners light
6) after a delay the main fan switches on to circulate warm air around the house.
7) main fan stopped in 2 minutes even though main burner has a light and running
8) Main burner turned on and off repeatly but main fan never come back (I can hear some high pitch noise it is trying to run and I can see main fan moves a little bit (1 lap in 10 seconds))

What I did so far,
Cleaned air filter.
Cleaned main blower motor housing & inside of furnase.
Replaced capacitor (7.5 uf 370v)

[mygirlsdad77]

You need a new blower motor. When it runs for a couple minutes, it overheats and shuts down. A new blower motor really should cure the problem.