[chhfsc]

have a payne 394jaw036045AAFA furnace, pilot doesn't come on, spark igniter doesn't click. Gas company service tech suggest to change the igniter, LH33WZ502 Model 990-195.
Found a used LH33WZ510 Model 990-516 locally, is that a direct replacement for LH33WZ502 Model 990-195?

 

[supers05]

I would want to say so, but they don't punish much details on those, like output voltage or spark gap. It should work.

That furnace model number doesn't seem to bring anything up either.

Cheers!

 

[roughneck]

From the symptoms you noted, it doesn't sound like it's the ignitor.

 

[chhfsc]

From the symptoms you noted, it doesn't sound like it's the ignitor.

What could it be? With the thermostat turn on for heat, relay board click, there is 24 volt on T1 and T2 of the ignitor terminals, but no spark.
What should I check?

 

[chhfsc]

What could it be? With the [COLOR=blue !important][COLOR=blue !important]thermostat[/COLOR][/COLOR] turn on for heat, relay board click, there is 24 volt on T1 and T2 of the ignitor terminals, but no spark.
What should I check?

 

[roughneck]

Is the ignitor receiving power?

 

[supers05]

What could it be? With the thermostat turn on for heat, relay board click, there is 24 volt on T1 and T2 of the ignitor terminals, but no spark.
What should I check?

It sounds like the igniter.

Cheers!

 

[chhfsc]

Is the ignitor receiving power?

The ignitor has 24 volt on the T1 and T2 terminals.

 

[chhfsc]

It sounds like the igniter.

Cheers!

I replaced the ignitor, the pilot lit on the first try. But furnace would not come on.
Went thru the reset procedure - turned off power and pilot, waited more than 5 minute, then turned power and pilot back on - there are sparks, but now pilot does not lit.
Is the gas valve stuck? Or the controller?

 

[roughneck]

Is the gas valve being powered? What's gas pressure, both inlet and manifold?

 

[supers05]

This is common. Where one failed part causes others to be stressed and also fail. Again that model number didn't give results. Is it actually a 349GAW? Does the wiring diagram look like this?

http://ww2.justanswer.com/uploads/brewster/2010-03-14_015104_payne_schematic.jpg

If this is like your unit, then Is there 24v at the gas valve, across 1 and 2. (may be TH and TR) How about between 5 and 3? How about 4 and 3? There would require 24v across 1 and 2, as well as 5 and 4. With the wires off, they should show continuity. (some resistance valve less then 200ohm or so.) If is all present, then it would sound like the gas valve is stuck. You'd have to change it.

If course, this is all guestimation based on a single letter of that model number.

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