Skip to main content ↑ ↓
Topic: Thermostat Fails to See Furnaces (Read 886 times) previous topic - next topic

Thermostat Fails to See Furnaces

Our Duo-Therm Comfort Control Center failed to see our furnaces for a while today. After cycling the power, pulling the thermostat, resetting connectors in the stat, and resetting connectors in the AC units, operation was flakey. It refused to see the furnaces and would not even operate the fans in the AC units. I also cycled that 12V with the switch in the step well.

We were only about 14 miles from the Camping World in Council Bluffs, IA. We went there are found they were closed for the holidays. (?!!!) The thermostat miraculously found the furnaces and has been working fine through the afternoon.

Keeping a spare may be prudent. Are there other gremlins that might cause such a problem?

All other systems were up and running well. Water pump, inverter, and lights all worked properly. Dash gauge showed appropriate voltage while traveling.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Thermostat Fails to See Furnaces

Reply #1 –
Quote from: J. D. Stevens –
Our Duo-Therm Comfort Control Center failed to see our furnaces for a while today.

We were only about 14 miles from the Camping World in Council Bluffs, IA. We went there are found they were closed for the holidays. (?!!!) The thermostat miraculously found the furnaces and has been working fine through the afternoon.

Keeping a spare may be prudent. Are there other gremlins that might cause such a problem?

Dave,

I vaguely recall reading about someone having a fluorescent light ballast interfering with their Duo-Therm control.  I can't recall if it was here, Escapees, or on rv.net that I read about it.  I know one of ours lights interferes with the A/V IR eye.

You might try experimenting with the lights in your coach to see if you can duplicate.

Michelle
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Thermostat Fails to See Furnaces

Reply #2 –
There is a fuse up on a board on the roof. If that fails then the thermostat fails to see things.  Also the dip switches have to be set right but that should not be an issue. I would look first in the AC unit. There is a connector in there that is in series. If that connector goes bad then every thing is not going to work correctly. Pull the thermostat off the wall and walk to the rear and look for the phone line type connector and connect it directly to the thermostat and it should work. You can replace that connector first and see if that keeps it running. I would not do anything till you have a warm place to store the coach if you need it later as long as it is working now. If it flakes out look at the connector first.
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: Thermostat Fails to See Furnaces

Reply #3 –
Quote
...
You might try experimenting with the lights in your coach to see if you can duplicate.
...

During the course of our current trip, we have had all of our fluorescent lights on and off in various combinations with no apparent affect. When the thermostat failed to work, it was midday and there were no lights on. We think about that if the flakiness returns.

Many CF lamps block infrared remote signals. Some settle down after they have warmed up. There are some sensors that claim to be less sensitive to CF lamp interference.

I am not aware of any unusual RF interference (RFI) during the flakey period. We used no transmitting devices other than cellular network devices with no auxiliary amplification.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Thermostat Fails to See Furnaces

Reply #4 –
Quote from: John Sichenze –
... Pull the thermostat off the wall and walk to the rear and look for the phone line type connector and connect it directly to the thermostat and it should work. ...

I unplugged/plugged the connecters that were easy to reach from inside. I like the idea of moving the thermostat closer to the control board (now that you told me the location of the control board). All has been working great since we stopped to try to buy a replacement stat.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Thermostat Fails to See Furnaces

Reply #5 –
J D, the old 4 button thermostat is no longer available, if you need to rebuild your thermostat it can be sent to Dinasour Electronics, they can rebuild it.
The selected media item is not currently available.Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi  Build# 5174 MC#17094

Re: Thermostat Fails to See Furnaces

Reply #6 –
Quote from: Bill Willett –
J D, the old 4 button thermostat is no longer available, if you need to rebuild your thermostat it can be sent to Dinasour Electronics, they can rebuild it.
Or you might be able to fix it yourself.
duo_therm_control_center_repair
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Thermostat Fails to See Furnaces

Reply #7 –
Howdy J.D. 
I recently exchanged my 4 button thermostat for a rebuilt.  Contact William Hendrix  whendrix@aol.com
Rebuilt works great!!
Dave Abel  dave_abel74@yahoo.com
Dave and Nancy Abel
'00 U320 36' WTFE  Build #5669
'10 Jeep Wrangler Unlimited Rubicon
Livingston, TX  SKP's Fulltiming

Re: Thermostat Fails to See Furnaces

Reply #8 –
For what it's worth, the upgrade to a five-button is fairly easy. If I can do it, (literally) anyone can.
 
Chad - '98 U320
Wickenburg, AZ
Chad & Judy
'98 U320 - Build #5315
Motorcade 16317
Wickenburg, AZ

Re: Thermostat Fails to See Furnaces

Reply #9 –
Quote from: Chad and Judy –
For what it's worth, the upgrade to a five-button is fairly easy. If I can do it, (literally) anyone can.
 
Chad - '98 U320
Wickenburg, AZ
Instructions
replacing-duo-therm-thermostat
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"
 

Re: Thermostat Fails to See Furnaces

Reply #10 –
Quote from: Chad and Judy –
For what it's worth, the upgrade to a five-button is fairly easy. If I can do it, (literally) anyone can.
 
Chad - '98 U320
Wickenburg, AZ

We have a 5 button unit. It has worked great except for a period of about three hours a couple of days ago. When it lost the furnaces, I unplugged/plugged cables in the stat, the front AC, and the rear AC. There was no immediate difference. A few miles down the road, it started working properly. ???
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX