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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I a Gibson/nordyne kg7tc060d 24b. Control board reads 1 hour

Customer Question

I a Gibson/nordyne kg7tc060d 24b. Control board reads 1 hour lockout. I reset the 2 resettable limit switches (not tripped).
Thermostat calls for heat- igniter glows- relays click- gas valve clicks- but burners don't fire
Submitted: 11 months ago.
Category: HVAC
Expert:  airheatman replied 11 months ago.

Do you have a meter to verify 24v at gas valve when you hear the click ? Also are you sure we have gas to furnace?

Customer: replied 11 months ago.
Gas supply is good. Yes, I have a multimeter, and am familiar with its use.
Customer: replied 11 months ago.
Should the limit switches indicate continuity?
Expert:  airheatman replied 11 months ago.

Yes limits should all show closed. but igniter should not light if limit is open. Lets check terminals on valve and make sure board is sending voltage to valve.

Expert:  airheatman replied 11 months ago.

Furnace always fires on high fire so check between C and HI terminals

Customer: replied 11 months ago.
Where are these terminals located?
Expert:  airheatman replied 11 months ago.

On side of gas valve.See below

Expert:  airheatman replied 11 months ago.

We should get 24v here when igniter glows and you hear the click

Customer: replied 11 months ago.
My situation is this. The furnace is located in an area with no cell service. So let me ask for a couple of possible solutions. If I get 24 V across the terminals, does this indicate bad gas valve? If I don't get 24 V across terminals, what is the solution?
Customer: replied 11 months ago.
Would it not be rare for the gas valve to have gone bad?
Customer: replied 11 months ago.
Furnace is only 1 1/2 years old.
Expert:  airheatman replied 11 months ago.

. If you are 100 per cent sure we have good pressure to valve and get 24v , valve is bad. If not, most likely connections or bad board.These valves do fail although they are not as frequent as other parts.

Customer: replied 11 months ago.
Furnace has been converted to LP gas, and been operating flawlessly for a year and a half. Is there a simple way to verify pressure at the valve (loosen gas connection and listen?) without having a water column indicator or other expensive tools?
Expert:  airheatman replied 11 months ago.

You would need either a manometer or pressure gauge.Just because we have some gas does not verify the necessary 11 to 14" needed .If valve is opening you should at least get a faint smell though even if not enough to ignite.

Customer: replied 11 months ago.
Why would it be different than a week ago?
Expert:  airheatman replied 11 months ago.

That is a hard question to answer.Sort of like asking why a light bulb worked last time it was turned on but doesn't now. Parts fail. Things change.Our first step is to determine if we are getting the voltage to the valve and then if we have proper pressure into valve.

If no 24v, board may be failing, if voltage but insufficient pressure a regulator may be failing and if 24v and good pressure, valve is failing.

Customer: replied 11 months ago.
OK. I'm going to take a drive out there and see what I can do. Thanks.
Expert:  airheatman replied 11 months ago.

Let me know what you find.