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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 21552
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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Furnace lockout on GCVA070BX40. LED is one blink.

Customer Question

Furnace lockout on GCVA070BX40. LED is one blink.
Submitted: 9 months ago.
Category: HVAC
Expert:  Rick replied 9 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. First I’ll need some more info so I have a more complete picture of you situation.

1 flash is ignition failure. Does the igniter glow? do the burners fire up then go out?

Customer: replied 9 months ago.
The schematic label says that 1 flash is a "System lockout (retries/recycles exceeded). 8 Flashes is "Check ignitor or improper grounding). The ignitor does glow every time. The main burner never turns on.Previously, I was getting 2 flashes = Low fire pressure switch stuck closed. I changed the inducer blower and no longer get this code.
Expert:  Rick replied 9 months ago.

Ok, you need to check for 24 vac at the gas valve while the igniter is glowing. If you have 24 v at the valve leads and the burners don't fire up then you have a faulty gas valve. If you don't have 24 v then you either have a bad board or a bad connection between the board and the gas valve. I'm assuming you have adequate gas pressure at the gas valve inlet.

Customer: replied 9 months ago.
OK, I can check that around noon today.
Expert:  Rick replied 9 months ago.


Customer: replied 9 months ago.
Furnace runs now. I wonder if the control was in a hard lockout due to the number of lockouts incurred. I had the power shut off to the furnace all night long. What is the procedure to reset a hard lock out on this furnace? This is different than a soft lockout after three failed lighted attempts. If it runs now, what should I look at for preventive maintenance moving forward?
Expert:  Rick replied 9 months ago.

Cycle the power off, wait a couple minutes then cycle it back on to try and clear a hard lockout. This will only works with a few errors but a 1 error is one that should work. With a soft lockout the unit will retry on its own after a period of time usually 1 hour. One thing you can do for PM is to clean the flame sensor rod with steel wool. Also change the filters every couple months depending on how dirty they get