Number 2 AC thermostat

[RogerMilne]

Hi All,
My name is Roger. My wife and I are brand new RV'rs and went head first into buying a used Class A. More about all that later, but had a quick question, regarding the new AC units we had installed at Camping World.
So long story short, we had 3 New Dometic AC units installed and 2 multi zone Comfort Controllers to match.
Zone 1 is the Main Living area and has it's own separate controller. Zone 2 is the kitchen/ Bathroom area and Zone 3 is the Master Bedroom. 2 & 3 share a controller in the bedroom. So, the Zone 1 is set point at 70*F and in Auto mode is doing what is expected, Cycling on and off based on room temp. Zone 3 in the bedroom and set at 70*F and cycling as expected. Zone 2 is set up the same but won't cycle on because the Inside temp is reading 66*F when Zone 1 & 3 are both reading close to room temp around 70*.
So what I'm trying to figure out is where the Zones get their Inside temp reading from. 2 & 3 are the same controller but with way different Inside temps, so is the thermostat pulling a temp from an internal wet bulb or is the temp at the intake of the AC unit? but even so how could the temp be that much different. Any ideas would be helpful as I've lost all hope in the Techs at Camping World and don't want to deal with them again unless the controller or AC #2 is faulty.
Thanks in advance for the input.

[David T. Richelderfer]

Please enter your year and model of coach in your profile.  That would help us get oriented with the correct coach to help you.  I entered my coach's info into the signature area of my profile.

[RogerMilne]

Will Do Thanks for the heads up!!

[Carl Boger]

Roger,

I don't know what your set up is, but in general the middle AC unit seems to be reading to low.  I would turn off the front  unit for a while to see how the middle unit responds.  It the middle unit then functions more like you would expect, I would look at the middle unit to see where it was picking up the temperature signal from.  There is no telling where the Camping World Tech's put it.  The rear thermostat is obviously reading a low temperature.

[RogerMilne]

I won't sure if each AC unit has a thermostat bulb at the air inlet that it compares what the temp of the air being drawn in is Versus the set point on the thermostat. If I knew the tech's put it in the wrong location, then I could understand the strange drop on that unit, especially since 1 & 3 seem to be reading correctly. So I guess my investigation is going to go down the path of where is the wet bulb for the number 2 unit.

[Steve Huber]

Roger,
I believe there are DIP switches that control the T'stat and related AC unit. They are either in the AC unit or the T'stat. Check your manuals for location / correct settings.
Steve

[David T. Richelderfer]

In our bathroom, on the wall opposite the loo door and near the towel closet, there are three items - 1) a furnace fan speed switch, high, low, and off; 2) an overhead light switch; and 3) a small cover with slits about one inch in diameter.  It occurs to me that the bathroom temperature is read by what you call a wet bulb that is remoted from the bedroom thermostat and is located under that small, slitted cover.  The bedroom temperature, I presume, is read by the bedroom thermostat.

Our coach's heating/cooling system appears to be designed much like yours with three ACs (combination ACs and heat pumps), one in the living room, a second one just fore of the bathroom door but over the kitchen, and a third over the king bed in the bedroom.  A living room thermostat controls our living room heating/cooling (zone 1), while a bedroom thermostat controls both our bathroom/kitchen (zone 2) and bedroom (zone 3) heating/cooling.  Interestingly, all three floor heating units in the living room/kitchen are controlled by the living room thermostat and two fan speed switches.  The other two floor heating units, one in the bathroom and one under the bed, each have fan speed switches and are controlled by the bedroom thermostat.

The zone 4 area has its own preset temperature heater and is located in the curbside basement near the black/grey waste tanks.  All of the floor heaters in zones 1, 2, and 3, plus the zone 4 basement heater must get their heat from the AquaHot.

[RogerMilne]

Thanks for the replies everyone. Yeah it seems to be the remote wet bulb for the zone 2, which everyone mentions is off. Back at work this week but will dismantle the cabinet it’s attached to and see if I can find a connector and then a replacement wet bulb. It’s definitely reading almost 10* cold compared to the internal thermostat temps.

Learning a lot as I go. But I appreciate the helpful insights.