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-   -   Goodman HVAC system blower stuck on? (http://www.diychatroom.com/f17/goodman-hvac-system-blower-stuck-37685/)

OhNoes 02-05-2009 01:11 PM

Goodman HVAC system blower stuck on?
 
My dads 5 year old goodman hvac system has had a problem for a while and doesn't have the money to get it fixed. Its a split residential system when i say split i mean there's a air handler for upstairs which is in the attic and another air handler in the crawlspace. The one in the crawlspace is the one that's having the problem with the fan blower. The unit outside turns on and off just fine the problem is the blower inside the air handler will not shut off after the unit outside has shut off.

Also there is sometimes a low noticeable buzz when the AUX heat turns on. There is no problem with the unit outside nor is it from the thermostat the switch is always set to "auto" not "on". I know its the air handler blower i just don't know how to fix it to make it shut off when the unit shuts off like its suppose to. If anyone could give me any info on how to fix this, I would be most grateful. :)

chard 02-05-2009 10:53 PM

Need to give us some time to get home from our job to answer your questions.

The problem could be a stuck fan relay or a crossed wire between 24v and fan wire. But I would think the latter would keep the A/C on 24/7. Especially if you have an old mechanical t-stat.

So, I am going to say the blower relay is stuck closed.

OhNoes 02-06-2009 06:58 AM

Quote:

Originally Posted by chard (Post 225920)
Need to give us some time to get home from our job to answer your questions.

ya well other questions where being answered seemed as if mine was being skipped at the time, sorry about that.

Quote:

Originally Posted by chard (Post 225920)
The problem could be a stuck fan relay or a crossed wire between 24v and fan wire. But I would think the latter would keep the A/C on 24/7. Especially if you have an old mechanical t-stat.

So, I am going to say the blower relay is stuck closed.

thanks 4 the reply, the t-stat is a Honeywell T8411R, maybe the thermostat has problems too, it doesn't report the temp correctly sometimes either.

Heres the datasheet i found for the themostat http://customer.honeywell.com/Techli...0s/69-1037.pdf

Its a central air & heating. Idk if im using the right terminology or not..sorry I'm a kid, but don't let that stop you from helping, i may just be getting info all over the internet to try to see if i can fix it myself. I had fixed our other unit outside for upstairs which needed a dual run motor capacitor because a bug crawled on it and shorted it out. That was an easy fix, i just replaced the capacitor and followed the wiring of how the old one was. This...not so much. I can give you the air handlers model number if needed.

beenthere 02-06-2009 07:40 AM

Probably a bad sequencer.

A/C Williams 02-06-2009 07:52 AM

I agree that the fan relay is probably stuck closed. You may be able to test this by tapping on the relay with the back of a screwdriver. Not hard but just give it a few good taps and if its stuck if may shut down the fan and you will know. The relay will be black with wires coming out both ends. Follow the wires from the motor to the relay. Good luck

OhNoes 02-06-2009 08:34 AM

Quote:

Originally Posted by A/C Williams (Post 226008)
I agree that the fan relay is probably stuck closed. You may be able to test this by tapping on the relay with the back of a screwdriver. Not hard but just give it a few good taps and if its stuck if may shut down the fan and you will know. The relay will be black with wires coming out both ends. Follow the wires from the motor to the relay. Good luck

Thanks i will try that.


The problem isn't that bad as i make it sound. I could just leave it as if it was set to "on" but really just leave the switch on "auto" if it ever decides to shut itself off thats fine i mean its just the blower, its not gonna do any harm if its left on. Am i right?

I'm more worried about when the aux heat comes on, that buzzing it made. Its not doing it now but it did happen before, it seems to happen @ random.

chard 02-06-2009 08:51 AM

the buzzing is probably a heat strip contactor. It may need to be replaced as well.

blicket 10-27-2009 03:12 PM

Did you ever fix the problem? I have the exact same issue. Coincidentally or not, I also have a 5yr old Goodman with a recently replace Honeywell thermostat.

Graybeard 09-03-2011 09:24 AM

Quote:

Originally Posted by A/C Williams (Post 226008)
I agree that the fan relay is probably stuck closed. You may be able to test this by tapping on the relay with the back of a screwdriver. Not hard but just give it a few good taps and if its stuck if may shut down the fan and you will know. The relay will be black with wires coming out both ends. Follow the wires from the motor to the relay. Good luck

I am having the same issue. Is the relay located in the compressor unit or at the air handling unit? I see a solid state relay in the compressor unit, I also located a mechanical relay at the air handling unit. It's a White Rogers DPDT 24 VAC relay. I tapped on it with a screw driver handle, but it didn't make a difference.

Doc Holliday 09-03-2011 09:47 AM

Let's not forget about high temperature limit switches tripping. If the evaporator coil gets blocked up and the hot air produced by the blower motor has no where to escape to then that air just gets hotter and hotter until the limit switch trips. When that switch trips the unit is always trying to get rid of the excessive heat it has been "told" is inside of the system.

If you were to put the system in heating mode you would not produce heat, only the blower would come one. Tell tale way to know if the limit switch is tripped.

Graybeard 09-03-2011 09:59 AM

Quote:

Originally Posted by Doc Holliday (Post 720389)
Let's not forget about high temperature limit switches tripping. If the evaporator coil gets blocked up and the hot air produced by the blower motor has no where to escape to then that air just gets hotter and hotter until the limit switch trips. When that switch trips the unit is always trying to get rid of the excessive heat it has been "told" is inside of the system.

If you were to put the system in heating mode you would not produce heat, only the blower would come one. Tell tale way to know if the limit switch is tripped.

Is the limit switch like a breaker?

Doc Holliday 09-03-2011 10:05 AM

Quote:

Originally Posted by Graybeard (Post 720397)
Is the limit switch like a breaker?

No and there can be and usually is more than one. It'll be in the heat strips compartment or on the blower squirrel cage.

Graybeard 09-03-2011 10:09 AM

Quote:

Originally Posted by Doc Holliday (Post 720401)
No and there can be and usually is more than one. It'll be in the heat strips compartment or on the blower squirrel cage.

Thanks, is there a way to measure or test the relay with an ohm meter? I assume the contacts will be open when no power is applied.

Graybeard 09-03-2011 12:06 PM

Relay type...RBM 90-340. For future reference...I measured across the relay contacts (1 and 3) and they were shorted. Replaced the relay and that did the job. I just want to say that this forum is an invaluable source and reference for DYI projects. I've used it for tiling and plumbing questions as well as A/C issues.

Doc Holliday 09-03-2011 07:32 PM

Quote:

Originally Posted by Graybeard (Post 720461)
Relay type...RBM 90-340. For future reference...I measured across the relay contacts (1 and 3) and they were shorted. Replaced the relay and that did the job. I just want to say that this forum is an invaluable source and reference for DYI projects. I've used it for tiling and plumbing questions as well as A/C issues.

I'm glad the guys on this forum led you in the right direction. I like this forum as well, good people here.


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