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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 7776
Experience:  Furnace, A/C and heat pump specialist.
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My furnace won't Ignite. The ignitor glows. It doesn't seem

Customer Question

Hey. My furnace won't Ignite. The ignitor glows. It doesn't seem to be getting gad
Submitted: 10 months ago.
Category: HVAC
Expert:  airheatman replied 10 months ago.

Sounds like you either have a gas pressure issue if igniter is lighting . Do you have a manometer or gas pressure gauge that reads pressure in inches of water column.?

Customer: replied 10 months ago.
No I dont
Expert:  airheatman replied 10 months ago.

Do you have other gas appliances that are working properly?

Customer: replied 10 months ago.
Unless that is on the inlet to the home.
Customer: replied 10 months ago.
We do have a gas stove which is operational
Expert:  airheatman replied 10 months ago.

1. Do you have a meter to verify we are getting 24v to valve when igniter lights?

2.Do you hear the valve click?

3.Do you smell any gas at all?

4. LP or Natural gas?

Customer: replied 10 months ago.
Natural gas. I don't smell any. There was a faint smell in the piping when I was replacing the valve which seems like that would be normal. I opened the box with the burners to see if I could smell any. I did not smell any there that is why it seems to me it is not getting gas. Should the valve click after or before the ignitor starts to glow?
Expert:  airheatman replied 10 months ago.

Valve should click after igniter warms completely up. Do you have a volt meter to verify the 24v to valve?

Customer: replied 10 months ago.
I don't have one but I can go to home Depot and check.
Customer: replied 10 months ago.
Here is a picture of the valve. How would I check it
Customer: replied 10 months ago.
Sorry last pic didnt work
Customer: replied 10 months ago.
I just had my hand on the valve no click
Customer: replied 10 months ago.
Do I trace those wires back to the main control board?
Expert:  airheatman replied 10 months ago.

Unplug the blue and red wires at valve. Put meter leads into the fe,ale spade terminals. Turn thermostat to call for heat.After igniter lights up watch meter and see if we get between 24 and 28 volts.

Customer: replied 10 months ago.
OK and if I don't get the voltage there I maybe got a bad board out of the box?
Expert:  airheatman replied 10 months ago.

That is correct.Board should automatically send voltage to valve after a preset time (Usually 17 to 20 seconds) after igniter starts to glow.

Customer: replied 10 months ago.
Alright I will go get a meter that reads ac
Expert:  airheatman replied 10 months ago.

Let me know what you find.

Customer: replied 10 months ago.
One more question. After a valve is replaced will it sometimes take a few attempts to light or should that light on the first try?
Customer: replied 10 months ago.
Suddenly it fired up and now is firing on a consistent basis.
Expert:  airheatman replied 10 months ago.

May have had air in gas line then.

If you have further questions, please let me know.

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