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Topic: a/,c thermostat power (Read 479 times) previous topic - next topic

a/,c thermostat power

my friend wendy owns Ted and Karen's 2001 U270 now. She is having rear a/c issues.  Some tech she found checked it out and replaced a capacitor. Anyway that didn't fix it .  But now she has no power to the thermostat to control zone 1. Is there a fuse for the power or a transforner to supply low voltage?
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: a/,c thermostat power

Reply #1 –
On an 01 the 12vdc to the A/C units come off the self resetting breakers that are hid behind the kick panel just as you come in the front door on the right side.  Now I am setting here in a foot cast so from memory it should be somewhere between breakers 50 & 54. If the tech shorted something out it may have killed that breaker.

Now if he was around the board that is hid in the A/C unit changing the capacitor he may have accidentally moved one of the dip switches causing it not to recognize the thermostat.
Mike

Another thought. Take the filter cover off both units and see if the communication cable has came unplugged.
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: a/,c thermostat power

Reply #2 –
Hi,

Yes, there is a 3A fuse in each air conditioner circuit board - inside a galvanized metal box with an inspection plate you can remove. You sholud be able to pull down the filter grill from inside the coach to find it. That would be the first place to check. Or possibly the tech did not plug the phone type cords into each air conditioner?? Also, some manufacturers will put a separate 12 volt fuse /circuit (hopefully resettable) for air conditioners.

Jim
Jim Frerichs
2002 U320 42'

Re: a/,c thermostat power

Reply #3 –
Thanks y'all for chiming in
Not sure if this RV repair guy is up n up??
2nd one
1st one in park I was in last week thought he diagnosed down to replacing the power board and one of the capacitors in my back #2 a/c
I ordered the board and he said he could use a different capacitor than the 20-10 that was there cause he could only get a ?30-10 without waiting weeks for delivery.
When board came in he put in and just like initial problem- kicked fuse at bed off. But this time it also threw the pole main off. I realized cause water came down on floor from unit #1 (front a/c)
Went to reprogram #1 after resetting main
And the whole thermostat was dark. No power to it or it got fried.
2nd repair guy
Says he's going to get some newer style 12 button?? thermostat vs the original comfort control duo-therm 5 button because ....it's old and he believed the 'new ' board I got was defective. He said if I got a new unit in the back- I'd have a newer style thermostat and that the front unit board would have to be replaced too because it wouldn't work with the new thermostat ( apples and oranges he said)
Or he'd just get 2 new boards and a newer style thermostat. Replacing the one in #1 either way that worked fine before the thermostat went dark.
That was Thursday
It's pretty hot
A lady loaned me a portable unit cause I was in distress from getting stung by bees.
He called from the parts store he was going to after not even getting up top to look and diagnose  himself  - was supposed to call me back to give the guy my card. An hour later i called because he hadn't called back and said he was going to go to a different place and would be here Friday. No show - then I see him at 8-9pm working on another rig - never even stopped here. Sunday at around 11 he drives by and asks my friend what we're going to do. At this point I'm thinking I'll just get an old style thermostat like I had and pray that unit #1 works - not happy ! But then says I owe him $125 after he left me hanging and never did get the parts.
My plan tomorrow is to just go get the old thermostat and have unit one and then I'll need to probably replace unit 2 completely.
He says the 5 button thermostat will not work with a new unit in #2. He says I'll have to replace the board in unit #1 - that they won't all work together. Does that seem right? I really no longer trust this guy and the lady I got the portable unit from says she's heard several complaints about him in this new park I'm in.

Re: a/,c thermostat power

Reply #4 –
You are going to have to replace the thermostat if you put in new boards.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: a/,c thermostat power

Reply #5 –
John
So if I replace unit 2 completely- it wouldn't work off of the 5 button duo therm thermostat?

My plan is to get SOME A/C today.
If I can just for now replace the thermostat that was there I'm hoping I at least have unit 1 working.

But are you saying that if unit 2 is replaced w new in my 2001 - the new unit #2 won't work with the old style thermostat?
Just to be clear. Thanks.
 

Re: a/,c thermostat power

Reply #6 –
John,

The 4 button thermostat (presuming it is OK) does not need to be replaced if you install replacement 4 button A/C boards. Be sure to set the dip switches the same as on the old boards. Depending upon the long model number on the component side of the 4 button board (usually ending in xxxxxxxxx.015; they are available from me. Boards ending in other numbers also may work for you depending upon if you have heat pumps, heat strips or not.

However, if you upgrade to 5 button A/C boards then you do need to get a 5 button thermostat. Those are available also. Boards and thermostats are not cross- compatible. If you are dead set upon going with the 5 button thermostat and boards, then don't bother with repair of the 4 button thermostat... please save the old thermostat for me.

Because 4 button A/C boards very seldom fail, I would suggest you are certain your thermostat is not at fault. If the push buttons are bad causing erratic selections of words on the display, then the thermostat's main chip is scrambled is the problem and the thermostat usually should be repaired before concluding the A/C boards are bad. The word furnace sometimes disappears from the display when this is the problem. Repair of the 4 button thermostat cures most problems.

If the push buttons are not bad, you might try doing the reset procedure. Bad push buttons will not allow the reset procedure to work.

To reset/reboot the the 4 button thermostat: turn on the thermostat power switch. Touch any button to turn on the back light. Before the light goes out, simultaneously hold down the up and down buttons. While still held down, press and release mode button. Then release the up and down buttons. Press and release mode button, the light must go out for a successful reset. Repeat if necessary.

http://bryantrv.com/docs2/docs/ccc.pdf

Jim
Jim Frerichs
2002 U320 42'