I am a professional re-work residential contractor/handyman that is trying to help out a customer. One paragraph is all i am asking for, not step by step help. The control panel is flashing 4 times and then a pause. The manual says this about the error message:
"4 RED FLASHES: This indicates that a primary or auxiliary limit switch has opened its normally closed contacts. The control will operate the supply air blower and inducer. This condition may be caused by: dirty filter, improperly sized duct system, incorrect blower speed setting, incorrect firing rate or faulty blower motor. Also, this fault code could be caused by a blown fuse located on the control board."
I checked the fuse and its good. I checked the Primary AND auxiliary contacts with no power to the furnace and my Ideal tester shows continuity. I assume the contact breaks when the system starts? Blower seems good as the forced air is as it should. Should I check these limits switches with power on and heat called?
Best regards Rick