Vent fan runs with ignitor but no flame or blower

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Vent fan runs with ignitor but no flame or blower

Postby Shadowanaheim » Sun Nov 11, 2012 11:52 pm

I have Payne furnace Model 395CAV036055 that is not firing when I turn up the thermostat. At the thermostat I hear it ‘click’ on when I turn up the temp. At the furnace I hear the initial Vent(?) fan turning on. The furnace is trying to light, I see an orange glow alternate on and off as if it is ready to start, but no heat. After about 3 minutes it shuts off. Gas is present at the furnace. Furnace just does’t light. Any ideas? Thank you!! I have an older model(10-14years old) and there are no led's or error codes.

I know there is gas at the valve(but don't know if it is getting through), could it be a bad valve?
I've tested the T-stat.
I've tapped and cleaned everything I can find, but want to make sure I don't break anything.
Should I just order a new mother board and start there?
I have tapped on the sensors(as suggested by other posts) and made sure all the wires have good connections.
The furnace has a clean filter.
What should the fire up procedure be? Blower then vent fan then glow plug then flame?
I can't figure out why the blower isn't turning on. When I switch the T-stat from Auto to ON the blower turns on for about 2 minutes then everything shuts down again.

When doing a self test run, everything did as the panel said it would.

Thanks for your help.
Shadowanaheim
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- Vent fan runs with ignitor but no flame or blower

Postby Freon » Mon Nov 12, 2012 12:17 pm

The fact you see the Hot Surface Ignitor (HSI) glow red and, I assume, hear the gas valve open manes the inducer fan is working and giving you the correct pressure in the combustion chamber. If no one has done any work on the furnace I would suspect the HSI as being the problem. It should glow white hot... hot enough to ignite the gas.

To be certain the HSI is getting the required 120 volts AC, you should measure the voltage at the HSI when the furnace is in a start cycle.

An HSI is not difficult to replace assuming relatively easy access. But with the new HSI be very careful not to touch the ceramic part that becomes white hot. Remove yours and take it to an HVAC supply house or, if you can get all the numbers off the HSI, you can order it online. Make sure you bring the furnace make and model if you go to an HVAC store.
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- Vent fan runs with ignitor but no flame or blower

Postby Shadowanaheim » Mon Nov 12, 2012 1:57 pm

Thanks I'll try that! I don't smell any gas(maybe because the fan is running). I don't hear the gas valve open.
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- Vent fan runs with ignitor but no flame or blower

Postby Freon » Mon Nov 12, 2012 10:43 pm

Take a hammer and using the wooden/plastic handle, rap the gas valve when you see the HSI glow. It's important to know the gas valve is opening before you buy a new HSI. Listen carefully for the "click" of the gas valve solenoid.
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