No Air from Air Handler - Help

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Old 05-28-06, 06:10 PM
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No Air from Air Handler - Help

Wanted to see if anyone could provide any assistance to the following problem: fan will not run on the air handler on my HVAC system.

Here's the deal: We had freon added to system this past Wednesday, but sometime during the night the inside circulating fan stopped working.

So far this is what I have tried-
outside compressor and fans runs, but the circulating fan will not operate on the air handler located in the attic. I have tried switching the t-stat between On & Auto, but the nothing happens. I have tried turning the fan blower by hand, but nothing. Have tried switching out t-stat with another unit & changing out capacitors, but that fan still will not operate.

Any assistance or advice will be greatly appreciated.
 
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Old 05-28-06, 06:48 PM
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No fan

If you are sure the fan does not run, as opposed to not getting air out of the vents, you may have a bad fan motor or bad fan relay.
 
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Old 05-28-06, 09:20 PM
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No Air from Air Handler

The fan blower inside the air handler is not working (and there is no air coming out of the vents). I have opened up the housing, and I do not see any loose wires or burnt wires in the area of the fan relay, but I have not removed it to be certain.

Is there any way that I can check to determine whether it is in the relay, or if it is the motor?

Thanks for the help!!!!
 
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Old 05-28-06, 09:32 PM
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Motor or relay

If you are getting power (could be either 120 or 240 volts) out of the relay & to the motor, there's a stong possibility the motor is bad.
 
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Old 05-28-06, 09:45 PM
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No Air from Air Handler

Earlier this evening, I did check the voltage going into the air handler and it was 24 volts (this was the low voltage terminal?).

If you are getting power (could be either 120 or 240 volts) out of the relay & to the motor, there's a stong possibility the motor is bad.

What would be the best way to check voltage out of the relay? The best place to check?

Thanks!
 
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Old 05-28-06, 10:10 PM
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Relay

Check at the load side of the relay, where the blower motor wires connect to it, with a multimeter. There should be a wiring diagram on the door to the blower compartment.
 
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Old 05-29-06, 10:10 AM
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No Air from Air Handler

unfortunately, there is no wiring diagram inside the unit, so to an extent I am winging it here.

I found the fan relay, and there are wires leading to it and from it. Having looked over many other postings, I am thinking that these are the lo volt terminal (in from the thermostat), and the high volt terminal (out to the fan motor).

When I checked the power on the wires in to the relay, I have power. Since my multimeter is a cheapee, it looks in the range of 240 volts. However, when I check the power leading out of the relay, there is nothing. Further, when I check the power going into the high volt terminal, there is nothing. Checking the power out to the blower motor shows a small amount of current, but nothing excessive (false reading perhaps?)

I am guessing, but wanted to run this past the experts, that I have proved that the relay is bad - but I wanted to get others opinions before removal.

Thanks for the guidance - when I get this fixed I promise to go back to my accounting, and leave this to the pros!
 
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Old 05-29-06, 10:26 AM
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These relays go bad fairly regularly if you dont feel confident bypassing it go get a new relay and try that. Only experienced techs thatcan positively identify low and high voltage sides should ever attempt bypassing a relay.
 
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Old 05-29-06, 10:41 AM
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No Air from Air Handler

By-passing a relay is beyond my talents, and a man has to know his limitations.

Since I have an identical unit downstairs, I am going to remove the fan relay from the non-working upstairs unit, and switch them out. If it still doesn't work, then by process of elimination, it has to be a burnt out fan motor.
 
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Old 05-29-06, 12:43 PM
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No Air from Air Handler

Pulled the fan relay from the non-working unit, and installed it on the identical HVAC unit downstairs. The fan blower operates!! Guess that this means that we have a bad fan motor on the unit upstairs. Sounds logical, right??

The unit is a Whirlpool (Not Frigidaire as I had earlier posted), Model NUGG075AF01. Would anyone have any websites in which these motors are sold? Or, does anyone know a website detailing how the fan motors can be changed out?

Whew, it is hot in that attic.

Thanks.
 
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Old 05-29-06, 02:12 PM
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Motor

It probably is the motor but I would hate to see you buy a motor & not need it. Most electrical components are not returnable. That equipment was made by ICP (Inter City Products) & the motor should be available at any Heil or Tempstar dealer. You may be able to use a generic motor available from any HVAC supply house. I suggest taking the motor with you when you go to get a new one.
 
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