Have HVAC Questions? Ask an HVAC Expert for Answers
Most heating and air conditioning questions require some diagnosing of the specific situation.Very few are one line asnwers .To be professional and provide you with an accurate answer may require me gathering some details such as model number on units and specifics on the issue at hand.To tell you to replace a part or exactly what is wrong with your unit without knowing this information would not be doing you justice ,would be less than professional on my end and a guess at most.Please provide information I ask for so that I can provide accurate answers to your specific equipment and situation. First give me the complete model on furnace as the 8000is just a series.
It will be on a label on inside furnace panel just above burners.Remove panel to burner compartment and look inside. The model number will help me give accurate assistance for your specific unit.
Below is a link showing where to find label with model number:
OK. Now does the inducer stop or does it keep running? The 21 is a gas valve lockout.Do you get any other code prior to that?
Follow this guide. Once vent motor (inducer comes )on, it should stay running the entire heating cycle.The inducer comes on, igniter lights, burners light, then blower comes on and all run except igniter until thermostat is satisfied, Then burners go off and blower and inducer goes off in normal operation
Doyou have a volt meter to see if we are getting 24 volts to the gas valve?
The chart I sent shows what to do if it fails along the path I mentioned.
Here is the chart again, Let me know if you can open it.I will get you a pic of gas valve
You should get 24 volts between C and HI and between C and MP when igniter lights
It has been awhile since replied.Just wanted to let you know I am leaving office for the evening.Will check back in tomorrow. We can go from here