Originally Posted by kgrenon
I had the E1 error on the thermostat a couple of times this week running the furnace. It would go away with power down and start working again. Now we are camping and I notice E1 again and the furnace will not shut off. Remove all power and perform reset on thermostat. Now thermostat is showing a flashing zone 1 and lit zone 4. No options for HP or furn... so i pull inside cover off of AC and check phone connectors, there is an extra one in there connected to a black wire not connected so i swap them our. Reset thermo same same. What is my next step? Pull cover off top of AC and check dip switches? Maybe they have moved? Im lost and thankfully have a space heater.. thanks in advance.
Look to the little plastic RJ-11 phone union that connects the black data cable coming from the A/C unit with the gray cable coming from your t/stat. They fail on a regular basis and often need to be replaced.
The quickest way to check the integrity of the grey data cable is to connect another, known cable from the RJ-11 union right to the back of your t/stat. Be sure that the RJ-11 plugs are oriented correctly, as a standard phone cable will not work.
I'm sure that you can find the proper RJ-11 orientation either in your manual or on-line.