Is there a way to tell when a heater was built from the serial #? I have an H400 IDL but after doing some research it looks like there is an IDL1 and an IDL2 version and they use different parts. There is also a cutoff date in 2004 where parts changed but I am not sure if that was the actual conversion from the IDL1 model to the IDL2. The sticker inside the panel says Model No: H400IDL and Serial No. 31256009.
I cant find any dates inside the panel but I was thinking I had the older model because my manual says resistance across my motor should be 30 and 100 for the different wire combinations as opposed to something like 5 and 10 on the newer IDL2 manuals I have found online. I tested my motor and it falls within the range of the higher values listed in my manual.
The problem I am having is that after I turn it on it it will eventually cycle up the blower motor and act like it wants to start working but after a few seconds it will cycle the motor down again and then give an A0 code. Manual pointed to blower motor or vacuum switch for this code so I checked and cleaned the small vacuum hoses and checked resistance across the motor. That all looked good so I figured it had to be a bad vacuum switch so I ordered a new one along with a new vent pressure switch which I accidentally broke while checking some of the wiring. When I installed the new switches it immediately threw another code saying the vent pressure switch was bad. Could I have bought the wrong ones? I thought I had a pre 2004 IDL1 model so those are the switches I ordered but they dont seem to be working. Thanks in advance for any assistance.