Hello all,I need help with Ac. I have the 5 button duotherm. I have replaced the thermostat, one communication cable that was bad and the control board. Actually two of them. I have tested both communication cables the one going to front ac and the one to the back ac. Both are good and wired correctly. My units are the older penguin heat pumps. What am I missing turn thermostat off press the two buttons get the FF then release and get EE.Have checked the 12v and 110v and all good. All duotherm said in email is you have communication error. I Know that but why? Help!Thanks in advanced!

1. You do NOT need 120 volts for the system to work. Just 12 volts. You have that as you get the EE error2. YES, COM problem. The FIRST thing you do is connect a GOOD Com Cable to Zone one AT the UPPER board and the wall tstst to the test cable. Since you have Older penguins, the most common problem of EE error is corroded(rust) connections. EACH Penguin has a 2 beige JUMP(union) Phone type junctions from the Control boards. THOSE unions are where the rust forms. They are usually located right in front of the evaporator in the return air space and that air is moist hence they get corroded after years of use. Access those 4 (2 on front ac and 2 on rear AC), and you will probably find your problem.3. LAST, I assume you built your new COM cables correctly? They are NOT Phone cables. COM cables are wired in reverse, if you used PHONE prebuilt cables that is your problem. Doug

Thanks for the reply Doug! Both board's are new and the same result as with the old boards. I take it the unions you are talking about are the p1 and p2 jacks on the control board? If so they are new and clean. You do mention beige in color mine are black. I did make my own cables and checked the wiring 4 times and it is correct to the wiring diagram. Also checked with a cable tester and all reads good. I'm stumped. I have a 2005 Monaco Diplomat.

Inline CouplerI think this is what Doug is referring to. This is 4 wire but they make a 6 wire that you may need.

I will have to look closer. It looked like my communication Cable plugs directly to board without union.

Stevec4s wrote:I will have to look closer. It looked like my communication Cable plugs directly to board without union.Is your Control board in a 8 by 8 inch Galvanized Box? Right in front of the Evaporator? This is important. Depending on the AGE of the penguin determines WHERE the Control board is located. If the control board is MOUNTED and accessed from the TOP of the RV under a flat metal plate that has 2 screws, you will see 2 black 4 wire Com cables connected to the Control Board. THOSE black cables(about 18 inches long) go into the Evap area and have those splice unions that connect to the cable from the wall tstat and then go from the other to the rear Zone 2. ALWAYS disconnect the Rear Zone 2 from the Rear control board at those splice connectors. As I stated, you need to make another Com cable 2 or 3 feet long and do on top and connect the wall tstat direct to Zone 1 Control board with the other Com cables disconnected. Doug

Dreaded EE code | Good Sam Community

Stevec4s
Explorer
Aug 09, 2020
I have two furnaces. That is the front board. Zone1
dougrainer
Nomad
Aug 09, 2020
OK, you stated you swapped P connections on the Control board? Then it showed Zone 2 and Zone 2 functions? Did you have Zone 2 control board COMM cables connected at this time? Now, LOOK inside that P connection that did not work with a flashlight. Do you see any corrosion at all? You may have to remove the Galvinized cover on that box to get a complete look at the PC board. Check for corrosion on the board. There are 12 volt wire connections----BLACK and RED. Which Zone Board has the Black and Red connected to 12 volt power? The one in your pic(Zone 1)? The ONLY way Zone 2 would show up on the Tstat is if the DIP switches have Zone 2 turned on on the Zone 2 Board. The DIP switches are those white switches on that red block. IF you turn the DIP switch to Zone 2 on the Zone 1 board, then the tstat will show Zone 2. Zone 1 is the default Zone on the control boards and does not have a DIP switch. Last I asked for Year/Brand/Model RV. I need that. Doug
Stevec4s
Explorer
Aug 09, 2020
I have a 2005 Monaco Diplomat PDQ Sorry I thought I posted that earlier. Terminals have been cleaned with alcohol. All good there. It seems P1 is the culprit. When I unplug p2 going to the rear unit I get EE code again. Plug back in and see zone 2
The only pin switch in zone 1 that is on is 5 for the furnace. My 12v goes to my front unit zone1
dougrainer
Nomad
Aug 09, 2020
Plug the tstat into P2 and unplug the Zone 2 comm cable. You CANNOT clean the small pins in a Phone type connection if corroded. If you go to the bedroom Control board you will see Zone 2 DIP switch ON. What you can do is easy if the P1 is bad. SWAP the front and rear control boards. Put the NOW Bedroom Control board to Zone 2 and the furnace ON. Put the now front control board to Zone 2 OFF. You should now have the P1 and P2 operational and connect the bedroom Zone 2 COMM cable to the working P2 of the old front zone board. Doug
dougrainer
Nomad
Aug 09, 2020
BTW, A Tstat reset (FF/EE). All that does is verify the DIP switch settings and communication between the tstat and the Zone control boards. Nothing else. Doug

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