Humming Sound During Burn Period

[jaygreg]

Issue: Gas furnace hums during ignition =85 but blower works and output appear unaffected.

Details: I have an American Standard GUF120D E3 H 120,000 BTU natural gas furnace with a bonnet capacity of 96000 and a 1/5 hp motor. When the thermostat calls for the burner to ignite, I hear an electric hum like a motor trying to start. This continues for about half a minute during the burn, fades out, the burn continues for a short period longer, then the blower kicks in as usual.

I found a website with a flow chart of a common gas furnace mechanism

). Though this appears to be from a site dealing with mobile homes and my home is not mobile, I assume there are similarities. According to this chart, there=92s an =93induced draft motor=94 =96 different from a blower motor = =96 that gets triggered in the front end of a burn cycle. If that=92s what I have, I=92d venture to bet I need a new draft motor.

Anyone have sufficient knowledge to help solve this? I could use a flow chart for my particular furnace as well. I've emailed American Standard for a manual but if there's something on the web, I'd appreciate being steered to it.

[what a maroon]

Please hold your furnace up to the monitor, I can't see it from here to tell you what's wrong.

[TheHack]

jaygreg wrote in news:a7ae3824-9221-45aa-bdd5- [e-mail]:

Cause, it doesn't know the words.

[Steve]

Details: I have an American Standard GUF120D E3 H 120,000 BTU natural gas furnace with a bonnet capacity of 96000 and a 1/5 hp motor. When the thermostat calls for the burner to ignite, I hear an electric hum like a motor trying to start. This continues for about half a minute during the burn, fades out, the burn continues for a short period longer, then the blower kicks in as usual.

I found a website with a flow chart of a common gas furnace mechanism

). Though this appears to be from a site dealing with mobile homes and my home is not mobile, I assume there are similarities. According to this chart, there?s an ?induced draft motor? ? different from a blower motor ? that gets triggered in the front end of a burn cycle. If that?s what I have, I?d venture to bet I need a new draft motor.

Anyone have sufficient knowledge to help solve this? I could use a flow chart for my particular furnace as well. I've emailed American Standard for a manual but if there's something on the web, I'd appreciate being steered to it.

Maybe if you were to pick up the phone and call a local, competent(not the lowest price), licensed, insured, professionally trained HVAC technician, they can actually lay hands on, and find out exactly what the problem is. OTOH, if you had a service agreement, your furnace would have already been serviced, and the problem already solved, and repaired at a discounted rate.

Pay me now, or pay me later.

[jaygreg]

I'm after education, Steve. Looks like the resources are slim here. If the unit were "broken"... I'd be getting comments from the repairman!

[Steve]

I'm after education, Steve. Looks like the resources are slim here. If the unit were "broken"... I'd be getting comments from the repairman!

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Education is a good thing... I just had another class I attended last night...didn't see you there.

[Steve]

Details: I have an American Standard GUF120D E3 H 120,000 BTU natural gas furnace with a bonnet capacity of 96000 and a 1/5 hp motor. When the thermostat calls for the burner to ignite, I hear an electric hum like a motor trying to start. This continues for about half a minute during the burn, fades out, the burn continues for a short period longer, then the blower kicks in as usual.

I found a website with a flow chart of a common gas furnace mechanism

). Though this appears to be from a site dealing with mobile homes and my home is not mobile, I assume there are similarities. According to this chart, there?s an ?induced draft motor? ? different from a blower motor ? that gets triggered in the front end of a burn cycle. If that?s what I have, I?d venture to bet I need a new draft motor.

Anyone have sufficient knowledge to help solve this? I could use a flow chart for my particular furnace as well. I've emailed American Standard for a manual but if there's something on the web, I'd appreciate being steered to it.

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One small point... I doubt you only have a 1/5hp motor in a 120,000btu furnace....unless its the induced draft blower motor.....but like I said in another post, your local, competent, licensed, insured, professionally trained, HVAC technician can tell you if you *need* a new motor. We can't see it, hear it, or test it through a computer screen.

If you want education, call your local vo-tech and they will set you up.

[Stormin Mormon]

Might. If it was repaired by Shears. One time during my trying out period when I did work for Shears. My trainer put a 1/4 HP blower motor to replace a 1/2. Cause if he went back to the shop for parts, it would have penalized him. As it happened, he got credit for a first time complete. I wasn't very happy with him, but didn't have the authority to say anything.

[jaygreg]

.

If your still in class, Steve... maybe we better let someone else answer who has a bit more education than both of us!

[jaygreg]

.

...

Correction! That should be =93you=92re=94; not =93your=94. Know the differe= nce, Steve?

[Steve]

Correction! That should be ?you?re?; not ?your?. Know the difference, Steve?

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Its called "continuing education", and is required to keep up with the new technologies, and the changes in equipment lines, as well as the technical aspects. 5 - 7 semester hours a year is about right.

I guess your vocation doesn't require any additional training or education.

[Stormin Mormon]

As furnace and AC equipment changes, the manufacturers host seminars and classes for techs who are already in the field. This allows the working techs to learn new skills. [your you're] comment is a bit off mark, as [your, you're] trying to insult the guy, but [your, you're] missing the mark. I'll let you choose spelling in each case, and see if [your, you're] getting it right.

[jaygreg]

Hummm. Is that the way Jesus would answer, Mormon?

[Stormin Mormon]

I doubt it. He'd send the Holy Ghost to whisper the answer in your ear. I have to write on a computer screen. I'm so, so, earthy in my replies.