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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22541
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have a York Diamond 80 unit. Control board failed and

Resolved Question:

I have a York Diamond 80 unit.

Control board failed and was replaced two days ago. Heating worked great for 36 hours and quit again.

Symptoms are:
1. Plug unit in.
2. Exhaust fan starts
3. Igniter lights
4. 1st time I checked it, flame did light for about 45 sec.
5. Now flame does not light. I think I hear the gas valve click.
6. Fan continues to run and unit tries to light, but no flame.
7. Error codes are: Green when unit is plugged in - 1 Red flash as unit tries to light - 7 red flashes when I push the error retrieve button.
Submitted: 5 years ago.
Category: HVAC
Expert:  BillyHvac replied 5 years ago.




Can you verify if 24 v ac is present at gas valve when ignition should occur?



Customer: replied 5 years ago.

1st - 24VAC was present at the gas valve during ignition

1. Heater lit and has been heating for about 10 minutes. Temp at thermostat has come up 3 degrees.
2. Conditions: Fan and control panel panel cover was in place. Burner panel cover was off (NOTE: during earlier tries with no ignition, I held the fan/control panel access cover switch "Down"). Unit had been unplugged for 30-45 minutes.
Expert:  BillyHvac replied 5 years ago.

was burner cover on when it faaulted?



Customer: replied 5 years ago.
Burner cover was on when it first faulted.

Let me put the answers in time order.

1. When I first decided that the heater was no heating, I went to it, pulled the burner cover off, unplugged, replugged and watched the burner with the cover off.
2. During troubleshooting, I repeated the above several times and had the burner cover on and off.
Expert:  BillyHvac replied 5 years ago.


With cover off....has burner failed?



Customer: replied 5 years ago.
Expert:  BillyHvac replied 5 years ago.


Thank you,


and when failed...we mean ignitor glows but flame doesnt light at all?



Customer: replied 5 years ago.
Expert:  BillyHvac replied 5 years ago.



And out of 10 cycles done, how many times would estimate fault to be?



Customer: replied 5 years ago.

PS - Room temp at thermostat is at setpoint. We'll see if it lights again before long.
Expert:  BillyHvac replied 5 years ago.


and after each fault it codes 7?



Customer: replied 5 years ago.
Expert:  BillyHvac replied 5 years ago.

Do you have a long light or small propane torch?



Customer: replied 5 years ago.
Yes - Propane torch
Expert:  BillyHvac replied 5 years ago.


This is just process of elimination.


Sometimes a glow ignitor doesnt reach 1800 f in order to light gas. It glows but not hot eliminate this option we point torch beside the ignitor during start up and see if it lights reliably with torch...understand the point?



Customer: replied 5 years ago.

The unit just shut off at temp setpoint. I'll unplug it so it can come on till I get there, plug it back in and help the igniter with a torch if it doesn't light.

Is this correct?
Expert:  BillyHvac replied 5 years ago.
correct...we just want to eliminate whether gas is there but ignitor weak....or if gas isnt there...
Customer: replied 5 years ago.
Darned, contrary thing lit off like a champ. It did not need any help.
Expert:  BillyHvac replied 5 years ago.




Have you:


removed tube from pressure switch and cleared barbed fitting on furnace where tube attaches


check tube for cracks

no vent blockages

sensor clean with steel wool


None of these are suspect but good things to do as preemptive...



Your issue is either no gas

Poor ignitor

Or the 2 dont get together.




Customer: replied 5 years ago.
I've not done the preemptive stuff yet, but will.

Thanks for your help.

Do you have igniter part number and installation instructions by any chance?
Expert:  BillyHvac replied 5 years ago.

The part number is(NNN) NNN-NNNN/p>


example -


Any local heating contractor should have one also.



BillyHvac and 2 other HVAC Specialists are ready to help you
Customer: replied 5 years ago.
Thanks much for your help
Expert:  BillyHvac replied 5 years ago.

I wish you luck...and I am available for follow up.






Merry Christmas!

Customer: replied 5 years ago.
Some follow-up.

Ultimate cause of my problem turned out to be a loose connection internal to the gas valve. I noticed that when I measured voltage across the valve, everything worked. When I took the voltmeter probe off, the heater stopped.

I replaced the gas valve and everything is nice and toasty warm.

Thanks much for your help. It is really nice being able to troubleshoot with you.

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