DuoTherm Comfort Control Thermostat

[omegacanuck]

Hi all,

We got our new 1994 Kountry Star out for its maiden voyage on the weekend, and did find a few little here's and there's that we're having some minor issues with.

I'll start with a simple one, assuming that what I'd like can even be done. Our MH came with DuoTherm Comfort Control 5 button thermostats for the AC. It is an American unit, so the thermostat is in Farenheit. Being Canadian, we would prefer it in Celsius, but can not find a way to switch it.

Any ideas?

Thanks.

[Luv2go]

Found this on another site:

Ok i finally figured it out. Called Dometic and after 45 mins of waiting on the phone the lady told me that they only come in *F. (Not what they advertise) Called Canadian Dometic and its just a shipping center. Called Heartland Customer Service and left a message. No call back yet. So me being an electrician took the thermostat off the wall to look at it again. In very small writing at the bottom it says break for C. It's just a small line circuit. So I broke the line and guess what it's now *C. So if there are any others that would prefer *C just take it off the wall and break the line at the bottom of the Thermostat. Dometic should also put those instructions on how to select temperature readings in the manual as well instead of telling us it only comes in *F when its a quick fix to make the change. No offense to our friends south of the border but us younger generations never learned *F/ miles/ feet in school its all metric *C/ Kilometer/ Centimeter now.

Hopefully your version also has this "line circuit" (maybe he means a trace on the PC board that you cut with a sharp knife).

[Skip426]

My, manual says " the F vs C read out is determined , by the manufacturer at the time of installation " but doesn't say how.
Possible jumper wire to cut or a hidden dip switch.
Warning; something the manual won't tell you , mine has a low battery alarm , below 11v battery power it starts squeeling.
Note to ones self type faster.
Went through school during the change over , I'm still confused.
Although at -40 it's all equal . Burrrrrrrrr.

["007"]

On page 16 of this PDF it explains the the determination of Fahrenheit or Celsius is made by MFG at time of installation of system.
I see nothing mentioned for 5 button in this PDF.
No info for us to convert in either one of them.

[omegacanuck]

Yeah, I noticed that part about the determination of C vs F at time of installation as well, so wasn't sure it could even be done. Not 100% sure I want to switch it over bad enough to start messing with the circuit board. Good news is default temp for A/C is 70F, which I know is a good temp for the AC to be set at, so might just leave it at that. Certainly at the end of the day, I can use the good old 'if it's too warm, bump it down a couple degrees, if it's too cold, bump it up' method too

The heat function of the AC units for us is almost irrelevant as we tend to boondock mainly, and so we use the gas furnace for any heat we need. Even AC is only for those days when it's too dang hot, and for when you want to cool the MH down some from the day's heat just before going to bed.

[Dr4Film]

On page one of the supplied manual is a Canadian Dometic phone number that I would call and talk to them about the procedure to switch it from F to C.

BTW, these 5 Button CCC units are now obsolete and are now being replaced with the 12 Button CCC-2 controls.

Dr4Film ----- Richard

["007"]

I guess one would assume that the control boards in the AC's are compatible with this new 12 button Control Center.
I see no mention of dip switch settings.

[steveclv]

I have exactly the same coach - well if yours is the 38' version

I have been told that in order to change to the Mk2 version of the controller I would need to change the AC units or at least the control boards - apparently they are different which is a pity as I wanted the timer control of the new version.

Regardless of whether it shows C or F, it is wildly incorrect anyway. My inside thermometer shows 84 and yet the control center switches off the front AC at 77 on the control.
You have to learn the numbers that work for you regardless of what it thinks it is.

["007"]

Thanks Steve for that bit of information,I didn't think the control boards would work.

[omegacanuck]

Originally Posted by steveclv

I have exactly the same coach - well if yours is the 38' version

I have been told that in order to change to the Mk2 version of the controller I would need to change the AC units or at least the control boards - apparently they are different which is a pity as I wanted the timer control of the new version.

Regardless of whether it shows C or F, it is wildly incorrect anyway. My inside thermometer shows 84 and yet the control center switches off the front AC at 77 on the control.
You have to learn the numbers that work for you regardless of what it thinks it is.

You know, I was wondering about that. I have only ran the A/C a bit, basically to verify it was working and to try to see about the switch from F to C. One thing I don't care for on these control units, is that it seems to only display the target temp, not the current temp. I had the temp set for 70 (default temp) and I'm sure it wasn't down to 70 yet, but the A/C kicked out. Thought it was weird, so I bumped it down to 67, and sure enough, kicked back in for a bit. Knowing that the temp on these can be a bit wonky, might have to play with it a bit more sometime. (Not today, rainy and cold. Had to turn the furnace on when working in it )

[calhyatt]

Originally Posted by omegacanuck

You know, I was wondering about that. I have only ran the A/C a bit, basically to verify it was working and to try to see about the switch from F to C. One thing I don't care for on these control units, is that it seems to only display the target temp, not the current temp. I had the temp set for 70 (default temp) and I'm sure it wasn't down to 70 yet, but the A/C kicked out. Thought it was weird, so I bumped it down to 67, and sure enough, kicked back in for a bit. Knowing that the temp on these can be a bit wonky, might have to play with it a bit more sometime. (Not today, rainy and cold. Had to turn the furnace on when working in it )

We have the same 5 button controller and all it reads is the desired temp. Either Newmar or the PO installed a very nice Clock, date and temperature reading unit on the drivers side slide wall. That is the only way we know what the actual temperature in the motorhome is. I looked at my manuals and I see no way to change the temperature select display to "C anywhere in the manual. It is not even discussed in my publications.
Good luck....

[steveclv]

You probably already know this but there is a 2 minute delay before the ac will start each time - worried me the first time I found this out thinking that the ac was faulty

Also, open up the vents by pulling and rotating the circular deflectors and check to see that the roof hasn't 'delaminated' from the backing board. Mine had and so I bought some 4" screws and some thin strips of wood - I replaced the standard screws and put the wood as a backing plate so that when I put the screws in, they caught into the wood strip and compressed the roof sandwich back to where it should be.
This ensures that all the cool air goes into the RV rather than circulating in the roof spaces.

["007"]

The Newmar's have two venting duct system for exit and return venting.
Return vent has foam filters to be cleaned if poor air flow.

[steveclv]

Yeh, those black 'filters' get dirty very quickly. In fact they are so flimsy that I am tempted to clean/service the evaporators as I suspect that mine are going to be pretty grimy after 18 years (although the front ac has been replaced at some point)

I have already done the condensers and fitted new foam to seal the airflow on the roof.