Heating, Air Conditioning, Fridge, HVAC/Sporadic, Heater won't ignite

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QUESTION: Hi Jim, my heater is a York Steller Plus installed in 1994, Model number P2UDD16P11401C, Serial number EHCM457677 . The last couple of years I have had a problem where it fails to ignite after three attempts on itís own and will not try again, but the venter motor keeps running.  When this  happens  I turn the heater off and then back on and it will ignite and it might be Okay for a day or two, or a week, six weeks or more. It is never the same and there is no consistency. The heater has a White-Rogers 50E47 ignition control module with diagnostic light with self-diagnostic capabilities. When it fails to ignite after the three attempts the diagnostic light is flashing. According to the installation book , if the light is on continuously the module is faulty but if the light is flashing the problem is most likely in the external components or wring. Because this is so sporadic every time I have a York technician come out they are just guessing what is wrong at my expense.

Is there anything you can do for me before they just start replacing parts?

In the troubleshooting section of the book under Main Burner does not ignite it says 1. Check for voltage across the MV terminals of the module, if none, replace module. 2. Check electrical connections between module and gas valve. If all is Okay, replace gas valve. I take it this means if it will not ignite at all, where mine does after I reset it.
Thank you so much, Robert.

ANSWER: Robert,
Check the legend on your furnace to see what the number of flashes mean.
Or check the cycle when it try's to light to see where it fails.
1.vent exhaust.
2.igniter glows.
3.burner lights.
4.burner stays on.

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York Heater legend
York Heater legend  
Same
Same  
QUESTION: Thanks Jim, There are 19 items under the legend and it only tells what the abbreviation are. Example: FL is Fusible Link, RC is Run Capacitor, 1R is Relay and Blower Motor and so on.  I tried to put an image of the legend with this but it does not show up for me so I don't know if you will see it or not.

When the light is flashing it is continuous. Examble, it does not flash three times pause then flash three times again. I have not been able to check the cycle when it fails because it always fails overnight or when I am not home. However, I have been at the heater when it failed to ignite the first of the three times, but then it ignited the second time on it's own. When that happened, the vent exhaust came on, the igniter glowed, a few seconds later there was a click but the burner did not light and the igniter faded, the vent motor remained on. Two minutes later the igniter glowed, a few seconds later there was a click and the burner ignited. I can only guess this is what happens when it fails all three times.

ANSWER: Robert,
I could see the legends you sent but that's not what I'm talking about.
Usually there is a legend stuck in the same area as the led light that says something like 1-flash-?, 2-flashes-? etc. I don't have a manual on your furnace and I don't know " 1994, Model number P2UDD16P11401C, Serial number EHCM457677".
When the thermostat calls for heat the first thing that happens is the vent exhauster blower comes on which when running closes a pressure switch, if the pressure switch doesn't close the igniter won't glow, if the igniter glows you know the pressure switch is closed as it should be, when the igniter glows it allows the gas valve to open, the igniter glowing sends a signal that it's on and ready to light the gas at the burner, from the time the igniter glows and the gas flows is only a second if there isn't an ignition in that second the igniter and gas shut off and the furnace try's again, after three or four try's with no success the furnace locks out, when it's trying the LED sends the flashing signals, when it locks out the LED just flashes.
When the furnace locks out you need to turn the thermostat all the way down for a minute or turn the furnace power switch off and back on to reset it to try again.
Check the igniter to see if it's mounted close enough to the burner to light the gas quicker, check for covers off or drafts from the vent, anything that might disrupt the gas from meeting the igniter quick enough.

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Module
Module  

Around Module
Around Module  
QUESTION: Jim, sorry to take up so much of your time. I sent two more images one of the module and one around the module. There is nothing there. On the module is says if "Flashing light refer to service instructions". Like you, I thought there must be something somewhere. I have all the papers and booklets from when it was installed. I've been over each page and there is nothing addressing flashing lights.

The igniter was replaced 15 years ago but I will check it out. Is it possible that it is not getting hot enough, or is it they work or don't work?
The burner box seems to be air tight. The air intake pipe has a couple of elbows and is about 12 feet long so I don't think there could be a draft from it.

I agree, for some reason if the gas is there it is not igniting. Something has to have changed but I don't know what or why.
You sure do know more than the York technicians I've had here. Where do I go from here short of replacing parts or wait until it quits?
Thanks again for everything.
Robert

Answer
Robert,
Try loosening the mounting for the igniter and scooting the igniter a bit closer to the burner where the gas comes out.
Also check the vents wall cap, roof cap etc for things that might cause a back draft that could cause the gas to stray away from the igniter.
a second to light is not much time but it's better then an explosion even a small one.

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Jim Barnhart

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Fifty + years conditioning the air.

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Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

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