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 > Duo-Therm not working

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LVJ58

Las Vegas, Nevada

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Posted: 04/17/11 08:41pm Link  |  Print  |  Notify Moderator

bowl300 You might want to contact Dometic's Customer support service at phone: 1-800-544-4881

A few years ago I called them about an issue with our rear roof ac unit and they were very helpful.

Just a thought

Hope you get your problem resolved without too much difficulty.

Best regards..


Jim & Sherry Seward
Las Vegas, NV
2000 Residency 3790 V-10 w/tags & Banks System
2003 Suzuki XL/7 toad

robatthelake

Vancouver Island

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Posted: 06/22/11 10:47pm Link  |  Print  |  Notify Moderator

I'm guessing that by now You have solved the problem and resolved the issue.

I had basically the same problem with My Two Penguin A/C Units and Duotherm 4 Button Comfort Control Center. It turned out to be a Badly Corroded Telcom Jack on the Front A/C Control Board.

I removed the Board, ordered a Replacement Molex Jack which I had installed by a friend with a pencil type soldering Iron. Reinstalled the Board and hey Presto! Back in business!


Rob & Jean
98 Dutch Star Diesel Pusher ..07 Honda CRV AWD


ac650

N. Florida

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Posted: 09/21/11 09:30am Link  |  Print  |  Notify Moderator

I'm a retired Telecom and computer tech. Sounds like you may have a communication problem in the RJ-11 jacks. To test comm integrity, start with the on/off switch OFF on the comfort control unit. While holding both the Mode and Zone buttons down, turn the switch ON. The display should show "FF". Release the Mode and Zone buttons. If comm is OK the display will show both units in the off mode. If display shows "EE" there is probably an issue with the RJ-11 wires/jacks but you could have a bad board in one of the roof units. RJ-11 jacks are infamous for poor connections. Telecom guys HATE them!

If you get the "EE" code start by running continuity tests on all the flat data cables. This is a data chain from: Comfort Control to "J1" on the front unit circuit board; then "J2" of the front unit to "J1" of the rear unit board; then "J2" of the rear unit to "J1" of the third unit, etc, etc. Basically, in on J1, out on J2.

If the wiring checks out and the RJ-11 plugs are clean the next step is to check the RJ-11 jacks on the roof unit boards. On my Country Coach, the board is located on the passenger side of the roof units. Pull the 12v fuse that feeds the AC units and turn off the 120v breakers. Remove the fiberglass cover and look for a 6x8 metal cover held by two screws. Remove the cover and the board and capacitors should be visible. Remove the two screws holding the capacitors and carefully lay them back toward the rear out of the way. BEFORE REMOVING ANY WIRES, label them! If you don't have regular wire labels use masking tape and a marker. Make a layout drawing of which wire goes where on the circuit board. They all must go back correctly. Don’t reverse the two RJ-11 cables.

Be gentle. Remove all wires connected to the board. Some are 1/4" spade ends and some are plugs. There are (3) two conductor plugs and (1) 6 conductor plug. These have tabs that can be pressed to release the plug. The RJ-11 plugs are on the bottom and the release tab is on the inside/back. There are (4) plastic retainers, one on each corner, holding the board to it's mount. Release the hardest to get to first (lower left). A very small screwdriver works. Gently remove the board.

Take the board to your bench where you have a good light and magnifying glass. Inspect the RJ-11 jack wires for the slightest sign of corrosion or rust. They must be clean and bright. How you clean them is up to you. I started with spray on contact cleaner to blow out any loose material. Then wrapped some very fine steel wool around a cotton swab and polished the pins. Of course, this will leave some steel wool residue (BAD). Blow it out with air, inspect again and insure no contamination remains. Obtain some good quality no-corrode grease like used on an auto battery post or a quality dielectric grease, and coat the RJ-ll jacks thoroughly. The grease must be non-conductive and not soften plastic parts. It should not melt and runn off in hot weather. Coat the RJ-11 plugs when you get back on the roof. Do both boards!

Don’t reverse the boards. There is a dip switch on the boards that identifies it’s position in the data chain. On my coach with two roof AC units and a gas furnace, the front board has switch 5 ON (furnace) and all others OFF. This defaults the board to “Zone 1”. The rear unit has switch 1 ON to identify it as “Zone 2”. Check your installation manual.

Reinstall the boards in the roof units and reconnect all wires. Double check using your wire labels and drawing. Reinstall the 12v fuse and turn the 120v breakers back on.

At the Comfort Control, verify the switch is OFF. While holding the Mode and Zone buttons down turn the switch ON. Display should show "FF". Release the Mode and Zone buttons and display should default to both units in the OFF mode. If so - SUCCESS !! (“EE” should NOT be seen)

Set unit #1 to Cool and adjust temp low enough the unit will come on. Suggest set Fan to Auto so you know when the thermostat kicks in. It may take up to two minutes for the unit to come on. Be patient. After unit #1 is running, set unit #2 on also. Both units should work. If you have the heat pump option you can test it also, just adjust the thermostat higher than ambient. Again, be patient. It make 2 or 3 minutes for the unit to switch from cool to heat. You might want to test the gas furnace if you have one.

bmerpaw

1000 Islands Ontario Canada

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Posted: 09/21/11 10:21am Link  |  Print  |  Notify Moderator

We have to purchase a new thermostat/control switch about every two years. On my third one now. Most RV dealers carry them in stock. $90.00 or so pus shipping. Its just one of those things about a 2004 Newmar.
Bill


2004 Newmar Dutchstar 4009, Cummins ISL375
2005 Jeep Liberty Toad
Traveling Man

PAIRAJAYS

Washingston State

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Posted: 09/21/11 10:25am Link  |  Print  |  Notify Moderator

ac650 wrote:

I'm a retired Telecom and computer tech. Sounds like you may have a communication problem in the RJ-11 jacks. To test comm integrity, start with the on/off switch OFF on the comfort control unit. While holding both the Mode and Zone buttons down, turn the switch ON. The display should show "FF". Release the Mode and Zone buttons. If comm is OK the display will show both units in the off mode. If display shows "EE" there is probably an issue with the RJ-11 wires/jacks but you could have a bad board in one of the roof units. RJ-11 jacks are infamous for poor connections. Telecom guys HATE them!

If you get the "EE" code start by running continuity tests on all the flat data cables. This is a data chain from: Comfort Control to "J1" on the front unit circuit board; then "J2" of the front unit to "J1" of the rear unit board; then "J2" of the rear unit to "J1" of the third unit, etc, etc. Basically, in on J1, out on J2.

If the wiring checks out and the RJ-11 plugs are clean the next step is to check the RJ-11 jacks on the roof unit boards. On my Country Coach, the board is located on the passenger side of the roof units. Pull the 12v fuse that feeds the AC units and turn off the 120v breakers. Remove the fiberglass cover and look for a 6x8 metal cover held by two screws. Remove the cover and the board and capacitors should be visible. Remove the two screws holding the capacitors and carefully lay them back toward the rear out of the way. BEFORE REMOVING ANY WIRES, label them! If you don't have regular wire labels use masking tape and a marker. Make a layout drawing of which wire goes where on the circuit board. They all must go back correctly. Don’t reverse the two RJ-11 cables.

Be gentle. Remove all wires connected to the board. Some are 1/4" spade ends and some are plugs. There are (3) two conductor plugs and (1) 6 conductor plug. These have tabs that can be pressed to release the plug. The RJ-11 plugs are on the bottom and the release tab is on the inside/back. There are (4) plastic retainers, one on each corner, holding the board to it's mount. Release the hardest to get to first (lower left). A very small screwdriver works. Gently remove the board.

Take the board to your bench where you have a good light and magnifying glass. Inspect the RJ-11 jack wires for the slightest sign of corrosion or rust. They must be clean and bright. How you clean them is up to you. I started with spray on contact cleaner to blow out any loose material. Then wrapped some very fine steel wool around a cotton swab and polished the pins. Of course, this will leave some steel wool residue (BAD). Blow it out with air, inspect again and insure no contamination remains. Obtain some good quality no-corrode grease like used on an auto battery post or a quality dielectric grease, and coat the RJ-ll jacks thoroughly. The grease must be non-conductive and not soften plastic parts. It should not melt and runn off in hot weather. Coat the RJ-11 plugs when you get back on the roof. Do both boards!

Don’t reverse the boards. There is a dip switch on the boards that identifies it’s position in the data chain. On my coach with two roof AC units and a gas furnace, the front board has switch 5 ON (furnace) and all others OFF. This defaults the board to “Zone 1”. The rear unit has switch 1 ON to identify it as “Zone 2”. Check your installation manual.

Reinstall the boards in the roof units and reconnect all wires. Double check using your wire labels and drawing. Reinstall the 12v fuse and turn the 120v breakers back on.

At the Comfort Control, verify the switch is OFF. While holding the Mode and Zone buttons down turn the switch ON. Display should show "FF". Release the Mode and Zone buttons and display should default to both units in the OFF mode. If so - SUCCESS !! (“EE” should NOT be seen)

Set unit #1 to Cool and adjust temp low enough the unit will come on. Suggest set Fan to Auto so you know when the thermostat kicks in. It may take up to two minutes for the unit to come on. Be patient. After unit #1 is running, set unit #2 on also. Both units should work. If you have the heat pump option you can test it also, just adjust the thermostat higher than ambient. Again, be patient. It make 2 or 3 minutes for the unit to switch from cool to heat. You might want to test the gas furnace if you have one.


This is a pretty detailed and complicated procedure. If i was technically challenged, I would go to a repair facility?

Jim E

ac650

N. Florida

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Posted: 09/21/11 02:20pm Link  |  Print  |  Notify Moderator

If you get the "EE" code, you could just replace the boards in the roof units. This will give you new RJ-11 jacks. But you have to remove the old to install the new - so why not give the fix a try? Could save you $114 per board. I like to 'fix' things rather than replace. Be sure to no-corrode all connections.

ac650

N. Florida

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Posted: 09/21/11 02:21pm Link  |  Print  |  Notify Moderator

If you replace the boards be sure to set the dip switches same as the old one.

moisheh

North America

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Posted: 09/21/11 08:12pm Link  |  Print  |  Notify Moderator

There is a control box for that thermostat. It is a silver box and the cable from the stat plugs into that control box. That box has a 3 amp fuse. One never knows where to find that control box. Mine was mounted between 2 cupboard panels. Try following the wires from the stat. In my case the fuse was good but a mouse had eaten the wires!!

Moisheh

Cloud Dancer

San Antonio and Livingston TX USA

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Posted: 09/22/11 05:48am Link  |  Print  |  Notify Moderator

IMO it's a terrible and stupid system. You spend all that money for two air conditioners, and you can't use either one as a backup for the other. The first time I had a problem with mine is when I discovered this design deficiency.
That's the reason I modified my system myself. I made it so that each unit worked TOTALLY independently from each other, and each with its own CCC.
Now, not only do I still have air conditioning if one of the units fails, but it also makes the diagnosing of the a problem much more simple.


Willie & Betty Sue
Miko & Sparky
2003 41 ft Dutch Star Diesel Pusher/Spartan
Floorplan 4010
Blazer toad & Ranger bassboat

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