A/C Fuse Problem

[Hugh.vines@att.net]

Originally Posted by Hugh.vines@att.net

I connected mine according to the diagram that came with the thermostat and it blew the same fuse. Then I connected according to the diagram without high low switch changed fuse and everything was fine

And my yellow and green wires were reversed in the overhead ac unit. I just reversed the at the thermostat. Take the red wire and find the high fan

[reminckv]

I spent some time today tracing wires. I found only one red wire coming from the Atwood furnace instead of the two blues. When I connect the 12v + (white/red) , red from furnace reset to white, the furnace runs without blowing the fuse. Now, however, after connecting the Y terminal wire on the A/C to the Y on thermostat, green to green for fan and blue 12v -, neither the A/C fan or compressor will run. I think I have a ground problem. Only other thing I can think of is that the A/C board is messed up now. Fuse and A/C breaker are good.

[Hugh.vines@att.net]

Originally Posted by reminckv

I spent some time today tracing wires. I found only one red wire coming from the Atwood furnace instead of the two blues. When I connect the 12v + (white/red) , red from furnace reset to white, the furnace runs without blowing the fuse. Now, however, after connecting the Y terminal wire on the A/C to the Y on thermostat, green to green for fan and blue 12v -, neither the A/C fan or compressor will run. I think I have a ground problem. Only other thing I can think of is that the A/C board is messed up now. Fuse and A/C breaker are good.

If therm has battery’s don’t hook up - blue wire take all wires out touch each to red wire one at a time that will tell you what each wire is. Test red and blue with a volt meter if red is + and blue is negative tape up blue wir

[reminckv]

Thanks. I’ve identified all of the wires. My wiring from the A/C was crossed up too. Right before I had to stop I tried jumping the A/C but no response. I may have messed up the A/C control board unless it has a fuse or breaker that I’m not aware of. Not going to be able to work on it tomorrow.

[Hugh.vines@att.net]

Originally Posted by reminckv

thanks. I’ve identified all of the wires. My wiring from the a/c was crossed up too. Right before i had to stop i tried jumping the a/c but no response. I may have messed up the a/c control board unless it has a fuse or breaker that i’m not aware of. Not going to be able to work on it tomorrow.

[simidrm]

Sounds to me like the time delay in the a/c unit isnt working, when you go to shore power the a/c compressors are trying to come on while there still under pressure and pulling enough power to blow the fuse, have you tried waiting a couple minutes before turning them back on?
But I would think that would trip the 115v breaker and not a 12v fuse, maybe a issue with the transfer switch.

[reminckv]

Sorry for the delay and thanks to all who have helped. This morning I threw up my arms and went back to my original analog thermostat and rewired it like the original Thor wiring and low and behold, everything is working. The strange thing to me is that it is wired exactly like I had the digital wired that was blowing fuses when switched to heat. I don't understand it, but I think I'm going to order a different digital thermostat that others have used successfully.
Again, thanks to everyone.

[DavidR]

I think your Honeywell thermostat was wired wrong. The 12v wire is capped off and not needed with this thermostat. Connect the gnd wire to RC/RH on Honeywell. Connect the furnace to W on Honeywell. Connect fan to G on Honeywell. Connect cool to Y on Honeywell. The Honeywell is a house thermostat that uses 24volts. It is not wired like a house thermostat like the instructions that come with it. This should fix your problem. Thanks David

[16ACE27]

Originally Posted by DavidR

I think your Honeywell thermostat was wired wrong. The 12v wire is capped off and not needed with this thermostat. Connect the gnd wire to RC/RH on Honeywell. Connect the furnace to W on Honeywell. Connect fan to G on Honeywell. Connect cool to Y on Honeywell. The Honeywell is a house thermostat that uses 24volts. It is not wired like a house thermostat like the instructions that come with it. This should fix your problem. Thanks David

Well, not quite: you still need 12 VDC to the thermostat to control the AC and Furnace circuitry. The thermostat batteries don't do that.

[Glensouth]

I don’t know if turning of the inverter has anything to do with it but you can leave the inverter on. When you have ac on your rv, as when you start your generator or plug into shore power, the inverter has a circuit in it that bypass the batteries and goes straight through the inverter. Try that the next time.

[reminckv]

Thanks again everyone. After confirming that all systems work when connected to the original thermostat, and that my didital thermostat is no longer working correctly (likely due to my miswiring), I reread your posts and other threads on the subject. I have ordered the Honeywell TH5110. I'm attaching a pic of the way I think it should be wired. Your comments on my hand drawn schematic will be appreciated.

[16ACE27]

Originally Posted by reminckv

Thanks again everyone. After confirming that all systems work when connected to the original thermostat, and that my didital thermostat is no longer working correctly (likely due to my miswiring), I reread your posts and other threads on the subject. I have ordered the Honeywell TH5110. I'm attaching a pic of the way I think it should be wired. Your comments on my hand drawn schematic will be appreciated.

That is the exact thermostat I installed in my ACE 2&1/2 years ago. This is the Youtube video I used to install it:

https://www.youtube.com/watch?v=Ce3y4fgFvak&t=443s

[reminckv]

Thanks for the video 16ACE27. It is helpful. The bundle from the overhead A/C unit is pretty straight forward although I swaped one of the terminal connections so that Y at the A/C terminal is actually a yellow wire running to the Y at the thermostat. I can't imagine why Thor didn't do that. The green goes to green since I am currently using high fan only and the blue terminal connects to a blue wire which goes to a large white wire from the wall which is a common.

There are a couple of things that I noticed in the video though. In my coach, the solid red is 12v+ where it looks like the 12v+ in the video is white with red stripe. I'm pretty certain that the white/red in my coach is the furnace trigger wire. The other thing I noticed is that he connected both the blue from the A/C and the blue from the thermostat to the large white common and in other threads people have recommended not connecting the blue from the thermostat (as I noted in my schematic). So, I think I am on the right track with your and others help, but I am still scratching my head about these two points. Again, I am very appreciative.