Payne 394G stopped igniting


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Old 12-10-15, 12:45 PM
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Payne 394G stopped igniting

I am using Payne brand gas heater (394G model). It worked two weeks back, but now it's not even igniting. When I turn on the thermostat I hear a tick, means I assume thermostat is working ok, but not sure. I checked fuse, no issues.
Basing on the reading, igniter may be gone, but not sure how to check. Any suggestions or experienced trouble shoot will be helpful. Thanks in advance
 
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Old 12-10-15, 04:02 PM
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A description of your furnace is at:

http://dms.hvacpartners.com/docs/100...394G.25.5P.pdf

You have an intermittent pilot ignition system.

When the thermostat calls for heat, the circuit board should turn on gas to the pilot burner and a spark to ignite the pilot.

You should be able to hear the spark tick, tick, ticking if it's working.

Even if the spark isn't starting, check to see if gas is coming out of the pilot burner. You can use a gas match or a match on a stick to see if it's lighting.

If there is no spark and no gas to the pilot, the odds are pretty good that the pilot light/switch isn't turning on the 24 VAC to turn on the spark and pilot gas.

You'll need a multimeter that measures 24 VAC to check on that.
 
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Old 12-10-15, 04:05 PM
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If there is no gas to the pilot and no spark, you can try tapping on the pilot switch with the handle of a table knife to see if that jogs the switch into operating.

Don't pound on it! Just a light tapping to see if it will start working.
 
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Old 12-10-15, 04:52 PM
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Thanks a lot Pioneer, appreciated.
As per this (http://www.doityourself.com/forum/ga...t-turning.html) sugggestion, I cleaned pilot switch end and it started igniting and some times burners are lighting, but for some reason they are not working together means it's taking too long to turn on burners, then it's banging with loud noise, I guess due to gas accumulation. Fan is not coming/turning on. It happened twice. I got scared and turned off whole thing. Any suggestions are appreciated. Thanks for yourtime.
 
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Old 12-10-15, 05:09 PM
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Welcome to the forums.

This furnace looks to be in the 25 year old range. Have you ever had it professionally cleaned and checked out..... it sounds like now's the time.

It sounds like the burners need a good cleaning at this point. there is a carryover tube or area where the burners light one from another. That tube or ports appear to be plugged.... probably with rust.
 
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Old 12-10-15, 05:34 PM
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Thanks PJ. You are correct about it's age. I am living here for almost 20years (on/off) and I guess it was there since this place was built in late 80s (1989 or something).
If possible I will try to do it myself, if not I will hire a professional. If I clean burners, do you think the fan will will start working? I am really concerned. Thanks again.
 
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Old 12-10-15, 06:25 PM
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Usually the blower won't start until the burners are lit for a few minutes and the plenum heats up.

The burners need to be cleaned to insure proper lighting. Delayed ignition is dangerous. You may also need to clean the burner orifices as well as the pilot orifice.

Gas furnaces are not use until they break down appliances. They need routine professional cleaning.
 
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Old 12-11-15, 12:15 PM
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>


The burners should all light smoothly and pretty much instantaneously. When they don;t the condition you describe is called delayed ignition. Most furnace repairman have a few amusing experiences they had while learning about that.

What you notice is that there is a DELAY before the boom! That means there is time for you to observe the cause of the delay and to shut off the gas by turning the electric gas valve control to the off position, or to shut off the manual gas valve before the furnace.

If you practice doing that, you can avoid the boom. Also --- keep your face out of the way just in case!


Carrier burners should be taken out and cleaned once/year with a wire brush, and the pilot orifice on the three wire pilot should be cleaned as annual maintenance as well.

Remove two 1/4" nuts that hold a shield in place above the burners and remove the shield. Take out the 1/4" nuts that hold the pilot burner in place and gently bend the pilot tubing so you can remove the burner behind the pilot. Remove the burners and brush them off with a wire brush.

In particular, clean the "wings" that carry the flames from burner to burner. That's usually what causes the delayed ignition.
 
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Old 12-11-15, 02:31 PM
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You guys are awesome, thanks a lot. I actually started cleaning before checking your response. I followed exactly same steps you mentioned. Good thing is, it's relatively not that complicated to pull that stuff and clean. I brushed burners with wire brush and also washed them. As PJmax mentioned I also cleaned orifices, they are actually in good shape. I thought there may be problem with 'gas valve'. So far so good.
It's working fine when I tested. Since it's not that cold (nice weather in SF Bay Area - it may be actually warm at this time of the year) it's not running. I will keep you posted if I need further assistance. Good work guys, keep it going. Happy Holidays.
 
 

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