Bryant blower fan runs all the time

[Gary_602z]

Hello There!
I have a small problem that I hope somebody can help me out with!
My sister has a older (78?) Bryant NG furnace that the blower motor had an internal short on. I had to have a new motor put on it and I replaced the T-stat as it was old and her ex had taken it apart when he was trying to trouble shoot it.
Anyways it ignites and heats fine but the blower runs non-stop even after the t-stat is satisfied.
Somebody said that it could be a limit switch?
Model # on furnace is 394GAW048150

Thanks in Advance
Gary

[paul52446m]

Hello There!
I have a small problem that I hope somebody can help me out with!
My sister has a older (78?) Bryant NG furnace that the blower motor had an internal short on. I had to have a new motor put on it and I replaced the T-stat as it was old and her ex had taken it apart when he was trying to trouble shoot it.
Anyways it ignites and heats fine but the blower runs non-stop even after the t-stat is satisfied.
Somebody said that it could be a limit switch?
Model # on furnace is 394GAW048150

Thanks in Advance
Gary

How many wires is going to the stat? Does your stat have a blower on switch? Normally if the limit switch is open and that closes the blower circuit,
then the burner will not come on. Does this old unit have a electronic board,
or does it have a fan heat sensing switch? Paul

[HUCKSTER]

doesnt the belleville switch do that also when its bad

[paul52446m]

doesnt the belleville switch do that also when its bad

In 40 years a never heard of a belleville switch. What is it? Paul

[HUCKSTER]

its the thermal switch .i live in belleville and thats what they always called it,i thought thats what it was called.

[HUCKSTER]

plenum blower switch

[paul52446m]

plenum blower switch

Depending on what kind of switch it is, it might have a on and off temp. setting
on that switch. You might have to turn both setting up. If the off temp is set at 90 degrees than try turning it up to 100 degrees and see if it turns off. There isn't a push, pull switch on that fan switch, that push for on and pull for off?
Paul

[Gary_602z]

Thanks Guys!
The T-stat only has 2 wires and the blower runs with it disconnected. It has a spark ignitor ignition which I believe is your flame sensor also. the only other sensor I can see is right in front that is about 2 by 3 inches and has 2 wires going to it with one of them having something that looks like a diode in line on it. It has a metal box with a lot of wires coming out of it that go to the blower and gas valve and coil for the ignitor. Does that box also have a relay in it for the blower? I haven't tried to open it up yet.

Thanks
Gary

[paul52446m]

Thanks Guys!
The T-stat only has 2 wires and the blower runs with it disconnected. It has a spark ignitor ignition which I believe is your flame sensor also. the only other sensor I can see is right in front that is about 2 by 3 inches and has 2 wires going to it with one of them having something that looks like a diode in line on it. It has a metal box with a lot of wires coming out of it that go to the blower and gas valve and coil for the ignitor. Does that box also have a relay in it for the blower? I haven't tried to open it up yet.

Thanks
Gary

Ok it sounds like you don't have a heat sensing switch for the blower. It sounds like you have a electronic board. Does all the blowers wires come to this board? If there is no green wire on the G post then the fan relay on that board is stuck closed or points burned together. Paul

[Gary_602z]

Ok it sounds like you don't have a heat sensing switch for the blower. It sounds like you have a electronic board. Does all the blowers wires come to this board? If there is no green wire on the G post then the fan relay on that board is stuck closed or points burned together. Paul

Sorry I didn't get back sooner but it was a relay that was stuck.
Thanks again!

Gary

[Patriotic]

You probably already checked this but there is a switch on the thermostat for the fan. If in the "On" position, it will run ALL the time. In the "Auto" position it will run when the thermostat calls for heat.