A/C Problems

[jwm4007]

First day out in a couple of months. Turned on the A/C and zones 1 & 2 are working fine but no zone 3. Looked at the wall DuoTherm thermostat and zone 3 was blank. Did some searching and found the reset procedure and reset the thermostat. Turned it off and then on again and all three zones appeared. Set them for 72 cool and zones 1 and 2 came on but no zone 3. Went back to the wall thermostat and zone 3 was blank again. Tried the reset two more time each with the same result - zone 3 shows up for about 15 seconds then goes blank. Has anyone had a problem like this or have any idea what to check next???? Thanks, Jim

[Mike Canter]

Physically swap the two thermostates and then reset them both and see if the problem stays or not. If the problem stays the same then it is the circuit board in the AC unit that is bad

[jwm4007]

There is only one thermostat. There is a button that switches from zone 1,2,3

[Mike Canter]

So how many roof AC units do you have?

[H. Miller]

First of all, this is a Camelot 42' PDQ (wouldn't it be nice if everyone included this info in their signature?)
All the recent brochures indicate it has three 13.5 roof a/c's (heat pumps incl.) with A thermostat. Now all you a/c knowledgeable people can weigh in.

[Mike Canter]

Then the simplest thing is that Zone 3 AC unit does not have power going to it. The circuit breaker for that unit has popped. If you shut Zone 1 and 2 OFF and turn on Zone 3 in COOL by itself does that AC unit start up? If not then check breaker power. If that Zone #3 AC unit has power then I would be very suspect of the circuit board in the AC unit that supplies info back to the thermostat.

One question I have here.....has that Zone 3 AC unit always worked or is this a recently obtained mh?

[jwm4007]

Hi to all,

this is a new problem since last use (two months ago). Tried the suggestion to turn off zones 1 and 2. Zone 3 does not come on. Circuit breaker is NOT snapped. The unusual thing is the thermostat display screen is blank for zone three.

[Mike Canter]

Are trying this plugged into shore power or on the generator? Could be that you have lost one leg of 50 amp power. Try different power source and also check your main power to make sure you harbor lega

[Daveo0o]

I frequently see this same problem on my '09 Camelot. Zone 1 & 2 operate normally, and 3 is blank. At the moment I am watching this scenario with Zone 3 AC rooftop running merrily along. I have to wonder why, or for how much longer it will run... as I cannot adjust anything to do with that unit - cause its ALL BLANK. I have not tried touching up the solder on the thermostat, but it sounds like as good a plan as any. Suggestions ?

[Daveo0o]

The 5 button, DuoTherm thermostat is here: http://bryantrv.com/docs2/docs/ccc5.pdf
And resets or power cycles don't seem to have much effect. The odd part is this: Initially after reset the thermostat shows all zones and appears to function normally. Delay times are in effect, so none of the units starts up, but I am able to set the mode and temperature etc. After a minute or so zone #3 just blanks out. No additional user interaction is possible because the entire display is blank when zone 3 is selected. Then the delays expire and zone 3 starts up, even though the display is still blank entirely whenever zone 3 is selected. Curiouser and curiouser...

[Dr4Film]

The cable used to communicate between the 5 button thermostat and the roof-top A/C is a 4 wire data cable with a RJ-11 connector. Make sure that they are snapped into each end securely and that the cable is still good.

There is also a fuse on the control circuit board inside the roof-top A/C that needs to be checked whether it is OK.

Dr4Film ----- Richard

[clyon51]

Had the same problem several times. I would check the data cable connections between Z 2 & 3 and the 3amp fuse connection on Z 3 AC.control board.

[bshephard]

Originally Posted by Dr4Film

The cable used to communicate between the 5 button thermostat and the roof-top A/C is a 4 wire data cable with a RJ-11 connector. Make sure that they are snapped into each end securely and that the cable is still good.

There is also a fuse on the control circuit board inside the roof-top A/C that needs to be checked whether it is OK.

Dr4Film ----- Richard

We found corroded RJ11 connections/couplers at the rooftop units were the culprits. I either replaced the coupler or cut off/replaced the connector. I then taped up any connections I could. Make sure to crimp the new connector in the correct wiring direction.

[Daveo0o]

We made extreme negative progress today on this problem, and picked a 99 degree day to do it. We went from 3 roof top AC 's running to two, to none. The RV repair folks working on the problem tried resetting the thermostat, which seemed to kill zone 3 entirely. Then they tried replacing the RJ11 cable between zone 2 and 3, which killed everything else. I now have nothing on the 5-button thermostat, no power on either side of the 3 amp fuse in the center (zone 2) control unit, and no idea what to do next.

The 12V fuse box in the RV's center bathroom has no problems with any of its fuses, including the two labeled "Furnace" or "Thermostat". I have spoken with some OTHER RV techs, and the consensus is that the fuse on the 12V power source feeding the control board in the zone 2 unit (the ony unit of the 3 with a control board) is blown open. Also possibly the thermostat is blown. So I have been hunting fuses, but no joy so far. Currently the only line feeding the control box that has 12V on it appears to be one of the blue wires labeled "furnace". I am guessing so far that these two blue wires somehow control if the aqua-hot is being requested or not.

Does anyone have a suggestion?