Hi everyone, I appreciate any help you could provide, I'm going to give as much back story as possible to try and make my situation clear.

I own a home in north Florida and have been running the heat for a few months now on and off.

On Saturday morning I woke up to find that the thermostat was blank. This has happened in the past due to the condensate line filling with water and activating a float switch that shuts my system down. I found this wasn't the case, so next I checked the 5A fuse in my air handler and found it broken. I replaced the fuse, the system worked for a few minutes with the inside unit fan on, until I switched the system to heat and the fuse blew again.

I check the 24V circuit for shorts with a meter at my thermostat and found the C, O, and Y wires to be short to one another. I went to the outside unit, disconnected these lines, checked the thermostat again and these wires were now open to one another. I believe this narrows my search to the outside unit.

I disconnected the contactor and reversing valve solenoid from the main circuit board, checked and found no shorts on the board. I removed the two wires from the board to the contactor and found the contactor to be short, I believe this piece is in need of replacement.

I checked the resistance of the two wires from the reversing valve solenoid and found them to be short, I believe this piece also needs replacement.

Finally I left the outside unit controls unplugged from the thermostat, and with a new fuse the unit is able to heat on EMHT.


Does it seem as though these two pieces need replacement at the same time? I am suspect because I don't know that they have anything to do with one another and I don't understand why they would both go bad at the same time. Are either of these pieces very difficult to replace, I like to think of myself as pretty handy, although that can sometimes get me into more trouble.

Thank you in advance.

Try isolating the problem by disconnecting either the contactor or reversing valve solenoid one at a time to find out which one is actually blowing the fuse

I checked the resistance of the two wires from the reversing valve solenoid and found them to be short, I believe this piece also needs replacement.

Not exactly my area but I believe the leads of a solenoid valve would show continuity. Does not mean a short circuit.

Replace contactor only and see what happens.

Your going to have a continuity beep on any thing eletrical. If Not the windings are open and the part will not work. The Question is are you checking continuity or resistance of the windings? Each part is cheap and is known to go bad. A contactor can be bought at any local hvac company. The reversing valve coil may be a order item.

I'm having the same problem Exactly!! Let mr know the out come

My AC has been working for about a week now, I wanted to give it some time to be sure that the fix was good.

The first thing I did was go out and buy a second meter, my first one beeps continuity on the two components, there was no separate setting to show very low resistance. The new meter showed resistance of both components so that was not the issue.

I did some more searching of the wiring of the outside unit and found a small piece of bare wire that could contact the cover. I insulated this wire and put everything back together and my AC is working like a champ again.

Thanks for the help everyone!