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Topic: Duo-Therm Opportunity (Read 405 times) previous topic - next topic

Duo-Therm Opportunity

Opportunity for some expert advice.  We have a 1999 U320 42DGFE that has 3 Duo-Therm with Heat Pump units, model 620515, front unit is 630515.  Previous owner was living in it in Colorado up until March and all three zones were working.  When we picked it up Zone 3 was missing.  Previous owner said that we just needed to have Jim rebuild the spare T-stat.  Had Jim Frerichs rebuild one of the T-stats, all systems were "Go" according to Jim.  Replaced the existing T-stat with the one Jim repaired and did the "reset", still no Zone 3.  Spoke with Jim, he suggested a 3 amp fuse on the control board, checked today, fuse was fine, but replaced it anyway since I was there.  Still no Zone 3 after a couple of resets.  Tried the dip switches, 3 is on, the rest are off, but went ahead and switched them back and forth.  Still no Zone 3.  There is power at the board.  Any thoughts on how to find Zone 3?  I did find a note, previous, previous owner had the control board for Aft and Mid listed as number 3106482.015.  We would really like to move this from the loss column to the win column so any advice is much appreciated. 
Lonny and Roxie
1999 U320 DGFE

Re: Duo-Therm Opportunity

Reply #1 –
Do you have three AC units. ?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Duo-Therm Opportunity

Reply #2 –
Quote from: dicksop –
Do you have three AC units. ?

Yes Dick, it is a 42 foot coach.  We have 3 also on our 40 foot, but not able to help him out.  I was thinking the dip switches as well and he said he checked those.  Wonder if it is a tripped circuit breaker on the bed panel for that air?
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Duo-Therm Opportunity

Reply #3 –
Hi Lonny,

If all the A/C12 volt fuses are good and the 120 volt breakers are on then the most likely suspects are dirty plugs or jacks or the cable between the second and third units has been damaged. Be sure to do the reset procedure again after making any changes...including dip switch settings.
The problem most likely is not the thermostat. The circuit board or its connections also could be the problem. I do have the 3106482.015 circuit boards available.
Jim

2002 U320 42'
Jim Frerichs
2002 U320 42'

Re: Duo-Therm Opportunity

Reply #4 –
If zone 3 is missing from the thermostat, I would agree that it is the signal cable that runs from unit two to three. Clean and/or test the cable.
Looking for a first coach.