Duo therm 4 button tstat

erniee wrote:
http://www.frerichselectronics.com/

Click Here. Much easier :)

jluke wrote:
sorry for the late response here, been down with bronchitis ever since Christmas. looked at the board, could see where the contacts had come loose and decided that I didn't feel comfortable doing such fine soldering or spending the money or time on a 5 button change out. Talked to Mr. Frerichs on Christmas day, he was very helpful and I have a rebuilt thermostat on the way. He claims to have done over 300 of these and never had one returned. I might note that the existing tstat had been redone by someone else and the switch had been held down by some type of adhesive which had broken loose resulting in the broken welds. While I am not happy about having my motor home and trips hostage to a thermostat that can't be fixed/repaired on the road, at my age if I can get a few years out of this, I will probably be done with rving. Thanks to all who responded.

I got one of those 4 button units from him and am very happy with it. It works as advertised.

sorry for the late response here, been down with bronchitis ever since Christmas. looked at the board, could see where the contacts had come loose and decided that I didn't feel comfortable doing such fine soldering or spending the money or time on a 5 button change out. Talked to Mr. Frerichs on Christmas day, he was very helpful and I have a rebuilt thermostat on the way. He claims to have done over 300 of these and never had one returned. I might note that the existing tstat had been redone by someone else and the switch had been held down by some type of adhesive which had broken loose resulting in the broken welds. While I am not happy about having my motor home and trips hostage to a thermostat that can't be fixed/repaired on the road, at my age if I can get a few years out of this, I will probably be done with rving. Thanks to all who responded.

http://www.frerichselectronics.com/

The "conversion" is, replacing your AC control boards AND installing the 5 button wall CCC tstat. You MUST replace each AC control board with a 5 button control board. The main difference between the 4 button and the 5 button is 2 things.
1. the 5th button changes zones
2. The 5 button has a better Freeze Thermister that works for both AC's and Heat Pump models. You must replace your existing freeze control with the new Freeze Thermister and it does come with the control board kit. Doug

NO, they are not difficult to install. Plug and play.

I rebuilt the switches on mine and it works great now. Could have sworn I took some photos but can't find them. Anyhow, here is the write-up I worked from. It came from another RV forum.
jor

For those with thermostats that still work but don't respond to buttons well, here's the fix, no soldering required.  

It would take multiple button pushes to get my thermostat to switch mode, and it got frustrating.  I've heard of disassembling the switches to clean them periodically but wanted a better fix.  So...

An order to Mouser Electronics for new switches, I bought five @ $1.22 each.  They are exact replacements. 
Mouser number     PVA10AH2
Mfg. PN:          PVA10AH2
These are DPST momentary 23mm pushbutton switches.

Turn thermostat off.  Remove the cover from the thermostat, it snaps on.

Remove the screws that hold the circuit board, unplug the cable from it.  This is an electronics board so treat it gently and ground your body (touch something substantial and metal), don't shuffle over the floor in wool socks holding it etc. to eliminate any static charge before touching it.  

Set it on a padded surface on the table and look at the switches. Break out the reading glasses.  Using a small screwdriver or knife tip, you can release the retaining clips that hold the components of a switch together.  Release clips, withdraw the top, spring and contacts, noting how they are inserted.  They will only go in one way.

Now, take one of your new switches and do the same.  Use the new parts in the old switch housing and snap the switch back together. You've just rebuilt the switch.  

Five minutes max.  It sounds far more complex than it is.  There is a spring in the switch that can pop out, really doesn't matter though as you use the new spring. Repeat as necessary for any other hinky switches and carefully reassemble the thermostat.

I didn't take pictures of the procedure and it's pretty self explanatory once you look at it but can and will post pix if necessary.  I enjoy this fix on a daily basis and hope you do also.

Chuck

A paperclip works great as a little tool to slide under and hook the metal contacts and put them in place. Whole job took about 15-30 minutes with learning curve. If I had to do it again, 5 minutes.

I recently ordered these switches from Mouser.  Replaced contacts following your intstructions..
Thermostat works like new. 

What is exact model number of your thermostat?

Mine is a bad switch attachment. I could get a screen if if I wiggled it enough but not enen that now. I talked to the guy who refurbish hes these yesterda to no avail but concern is this could have happened on a long trip and there are no parts/repairs available. I understand the conversion to the 5 button unit requires a board for each a.c., are the difficult to install?

Turn off all fluorescent light fixtures, then reset thermostat and let it reboot.
If heating/cooling system works, leave lights along. Until end of trip.
When you get home, turn on system, then turn on fluorescents one at a time until system crashes.

Mine started acting funny, meaning intermittent stopping, about four years ago in my 2004 Country Coach. It was a bad ballast in one of the fluorescent ceiling units. Removed the ballasts and replaced with LEDs. Problem solved.