Dreaded EE code

[Stevec4s]

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!

[dougrainer]

1. You do NOT need 120 volts for the system to work. Just 12 volts. You have that as you get the EE error
2. 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