Goodman Furnaces (GMS9) strange issue with blower?
#1
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Goodman Furnaces (GMS9) strange issue with blower?
I have a Goodman Furnaces (GMS9) and just fired it up for the first time this winter and it's doing something strange only upon first cycle.
Here whats happening.
1. Call for heat
2. Everything appears normal as blower turns on
3. See glow plug turn orange
4. Propane ignites
this is where it get strange
5. Blower turns off with flame still lit...very short period of time that it's off. Maybe 2-5 seconds
6. Blower turns back on and unit works fine and continues until the call for heat goes away
Anyone ever seen anything like this?
Here whats happening.
1. Call for heat
2. Everything appears normal as blower turns on
3. See glow plug turn orange
4. Propane ignites
this is where it get strange
5. Blower turns off with flame still lit...very short period of time that it's off. Maybe 2-5 seconds
6. Blower turns back on and unit works fine and continues until the call for heat goes away
Anyone ever seen anything like this?
#2
It's possible the blower motor is overheating and cycling on overload but it should take more than a few seconds to reset.
You'll have to test the furnace with the blower access panel off. (tape or clamp the door safety switch and if you have a gas water heater in the room turn it off when doing this test)
A meter should be used to check the board's output to the fan. You can also listen for a relay click.
If the board is dropping power to the motor with the burners on, it's bad.
You'll have to test the furnace with the blower access panel off. (tape or clamp the door safety switch and if you have a gas water heater in the room turn it off when doing this test)
A meter should be used to check the board's output to the fan. You can also listen for a relay click.
If the board is dropping power to the motor with the burners on, it's bad.
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I'll have to do those tests, thanks for the recommendations.
For what it's worth, I just replaced the blower motor and control board last winter and it worked just fine to close out the winter so I'm aggravated that I have issues again! and this one has me puzzled.
When you say "it's bad" do you mean as in safety? Eventually, if the board dropped power to the motor for an extended period of time then I'd have to assume the limit switch would trip and shut the unit down.
For what it's worth, I just replaced the blower motor and control board last winter and it worked just fine to close out the winter so I'm aggravated that I have issues again! and this one has me puzzled.
When you say "it's bad" do you mean as in safety? Eventually, if the board dropped power to the motor for an extended period of time then I'd have to assume the limit switch would trip and shut the unit down.
#4
it won't pose a hazard due to the high limit but could shorten the life of the motor cycling it so much.
You should feel the motor when it's cycling and see if it's very hot.
Did you use the oem motor for repair? universal motors have to be properly matched.
You should feel the motor when it's cycling and see if it's very hot.
Did you use the oem motor for repair? universal motors have to be properly matched.
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I'm sorry I gave bad info. I didn't replace the blower motor. I replaced the inducer motor. The blower is what is cutting off one time on initial startup. After that one time it's ok until it reaches set temp.
I use all OEM parts.
I have an ecobee thermostat
I use all OEM parts.
I have an ecobee thermostat
#7
You can rule out the stat by disconnecting the wires on the board and jumpering R and W together.
If it behaves erratically it's probably the board, but like I said before monitor voltage output to the blower to be sure.
If it behaves erratically it's probably the board, but like I said before monitor voltage output to the blower to be sure.
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I just figured out the issue. It was setting in the ecobee thermostat. It was titled "fan control in heat mode" ether ecobee or hvac.
Mine was set on ecobee. When I changed it to hvac it is operating normally.
Mine was set on ecobee. When I changed it to hvac it is operating normally.