[tonygharris]

Hi All,

My Lennox G26 furnace works fine in the heat mode, but when it is switched to AC it trips the 3amp breaker on the side of the control box. Please help me troubleshoot this problem.

Thanks,

Tony

 

[beenthere]

Check the thermostat wie that runs from the furnace to the outdoor unit for damage.

 

[BayouRunner]

And if the wire is good check out the contactor. Sometimes the coil will go bad and cause a short

 

[yuri]

Check the thermostat wire at the outdoor unit for dog/rodent chewing, weed whacker damage or damaged insulation.

 

[user_12345a]

If there's no obvious damage...

Open the box where the circuit board is, is a metal cover...

Disconnect wire going to the outdoor unit - connected to Y and C at furnace.

Check resistance.

You shoudn't see a dead short, should see resistance of contactor, prob a few ohms.

 

[tonygharris]

Thanks, I'll let know the results.

 

[tonygharris]

Hi All,

The contactor coil was the culprit. Thanks again for your accurate diagnosis.


Tony