Hi All,

I came home today and the I discovered the air conditioner is not working. The symptoms are that the furnace indicator lights are not on which might indicate the furnace is not getting power. The blower does not turn on when the thermostat is sending a signal. Also, the outdoor AC unit is not turning on when the thermostat is sending a signal. What is the best explanation for this problem, possibly something wrong with the furnace circuit board, or maybe a wiring problem. Would the power loss at the furnace cause the outdoor AC unit to not turn on?

Thanks for your help in advance

CycloneGriff

Would the power loss at the furnace cause the outdoor AC unit to not turn on?

((yes it would)),
Did you check for kicked breaker or fuse to you furnace,the furnace has to have power in order to have the low voltage that turns your a/c on,, check breaker and let us know,, (the right way to check breaker is to turn completely off and then back on)

Also,, some circuit boards have a plug-in automotive type fuse in them you might want to look for that also, could be blown

Would the power loss at the furnace cause the outdoor AC unit to not turn on?

((yes it would)),
did you check for kicked breaker or fuse to you furnace,the furnace has to have power in order to have the low voltage that turns your a/c on,,,,,check breaker and let us know,,,,,,,,(the right way to check breaker is to turn completely off and then back on)

I did check the breaker, at least the ones that said furnace and AC. They were at the on position and I toggled them to off and then back to on. All the rest of the breakers were on. This did not fix the problem. Is there another fuse or breaker that is built into the furnace? I can't seem to find one. Model is Lennox G40UH(X) if that helps. If there is no fuse built into the furnace I don't know what else to check besides start measuring voltages and I think it would be safe to leave this to the technician.

Thank you for your help

also,,,some circuit boards have a plug-in automotive type fuse in them you might want to look for that also,,could be blown

Ah yes, there is a fuse on the circuit board and it appears to be blown. Any idea on how to get a new one?

A man has got to know his limitiations. If there is something you aren't comfortable with, have someone with knowledge and experience take care of it for you. But observe, ask questions and learn from the experience. The more you can learn, the less money you will burn.

Looks like I need a new 3 Amp blade fuse. Radioshack / Home Depot here I come. I wonder why the fuse blew though.

Could be a problem somewhere,, could be just a power surge caused it, have there been any electrical storms lately?

could be a problem somewhere,,,,,,could be just a power surge caused it,,have there been any electrical storms lately?

There were some storms today, don't know to what extent. What a dirty filter cause the unit to draw more current?

Although it is important to keep a clean filter,at all times,check them even more often if you have indoor pets,most like a fluke electrical prob. Get you a few extra fuses and keep them on hand,, the fuse is there to protect you circuit board, be glad it did its job