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I have a Carrier Weatherman 8000 furnace/ac. It passes the "self test." When I switch on the fan it starts after 1 or 2 seconds, the fan runs for 3 or 4 seconds, then the 3a fuse blows. What's wrong? Thanks.

Submitted: 165 days and 21 hours ago.

Category: HVAC

Value: $18

Status: AWAITING EXPERT REPLY

Posted by Rick Mather 165 days and 18 hours ago.

Answer

It has a direct short to ground most likely is the fan windings

165 days and 18 hours ago.

Reply

Durig the "self test" the fan runs for 10 seconds at high speed and 10 seconds at low speed without blowing the 3-amp fuse. Wouldn't that point away from the windings as a short candidate?

Posted by Rick Mather 165 days and 18 hours ago.

Answer

Not if there getting hot and then short out

165 days and 17 hours ago.

Reply

What would be the second most likely thing to short? What would the second most likely problem be?

Posted by Rick Mather 165 days and 17 hours ago.

Answer

Could be contactor coil, capiciator, bare wire scrapping, and transformer primary shorting out

165 days and 17 hours ago.

Reply

Is there a way to track down the short without just replacing parts until its fixed?

Posted by Rick Mather 165 days and 15 hours ago.

Answer

With an voltage and ohm meter. Radio shack as cheaper ones

Posted by Rick Mather 165 days and 15 hours ago.

Answer

With an voltage and ohm meter. Radio shack as cheaper ones

Posted by Rick Mather 165 days and 12 hours ago.

Answer

are you there

157 days and 8 hours ago.

Reply

You gane me advice on where to buy a volt/ohm meter but no advice on what to check with it.
The 3-amp fuse is on the 24-volt side. How can a short on the high voltage side of a transformer cause a fuse to blow on the low side?
There are several test points on the pcb, should I use those and what do I look for?
The only advice you have given is that a short can cause a fuse to blow.

Answer

Is the fuse thats blowing on the low voltage 24 vac side or is it 120vac or higher

Accepts:
Expert:	Rick Mather
Pos. Feedback:	96.1 %
Answered:	6/17/2009

HVAC Technician

35 years experience, HVAC

151 days and 9 hours ago.

Reply

I was about to run new wire from the pcp to the thermostat when I asked my question. I told you it was the 3-amp fuse on the 24 volt side. You suggested checking the motor windings for a short along with other items on the high voltage side. thanks to your wild goose chaseI ran out of time and had to call a service man. It turned out to be the thermostat wiring. You did not read my information and you steered me in the wrong direction. I do not accept your answer as it was not helpful.

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Question

I have a Carrier Weatherman 8000 furnace/ac. It passes the "self test." When I switch on the fan it starts after 1 or 2 seconds, the fan runs for 3 or 4 seconds, then the 3a fuse blows. What's wrong? Thanks.

Answer

It has a direct short to ground most likely is the fan windings

Reply

Durig the "self test" the fan runs for 10 seconds at high speed and 10 seconds at low speed without blowing the 3-amp fuse. Wouldn't that point away from the windings as a short candidate?

Answer

Not if there getting hot and then short out

Reply

What would be the second most likely thing to short? What would the second most likely problem be?

Answer

Could be contactor coil, capiciator, bare wire scrapping, and transformer primary shorting out

Reply

Is there a way to track down the short without just replacing parts until its fixed?

Answer

With an voltage and ohm meter. Radio shack as cheaper ones

Answer

With an voltage and ohm meter. Radio shack as cheaper ones

Answer

are you there

Reply

Answer

Is the fuse thats blowing on the low voltage 24 vac side or is it 120vac or higher

Reply

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