Horizontal Heil problem


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Old 02-09-13, 04:58 PM
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Horizontal Heil problem

I have a similar problem with a Heil NHGE050CF01 horizontal furnace. When thermostat calls for heat the induced draft fan activate after about 5 seconds, the pressure switch activates the spark ignitor and the gas for the pilot opens and a flame appears for about 1 second and the valve closes and shuts the flame off. Inducer continues to run and cycle repeats over and over several times without a continuous pilot flame and no main burner flame ever. Changed to pilot ignitor assembly with one that cross referenced for a replacement with no improvement, or actually, same problem as before...where do I go from here? Thanks!
 
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Old 02-09-13, 05:50 PM
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There may be a flame sensing rod separate from the pilot assmb. It's usually on the opposite end of the burner rack from the ignition. Remove the flame rod & clean it with fine steel wool or a scotch brite pad. Reinstall, try it, & let us know.
 
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Old 02-09-13, 10:19 PM
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I have not been able to find a flame sensing rod on this furnace. The ingnition apparatus is basically a spark plug with the pilot turned slightly towards the burner such that the gas crosses the spark path. I have had the burner manifold out and do not see a sensor. The main burner is only two jets and the ignitor sits in between the two. Thanks!
 
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Old 02-10-13, 08:02 AM
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I have made you your own thread.
 
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Old 02-10-13, 03:45 PM
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Please post the make and model of the ignition control module.
 
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Old 02-10-13, 10:56 PM
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Honeywell S8600M. Assume it is original which would make it about 20 y/o
 
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Old 02-11-13, 02:03 PM
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If the 24 VAC to the TH terminal on the ignition control is being interrupted, it will shut off the pilot, so I'd check that to see if that's remaining energized.

When 24 VAC is applied to the TH terminal what should happen is:


1. the pilot valve on the gas valve is energized which turns on the gas to the pilot

2. At the same time, the spark should start.

3. The pilot should lite and stay lit as long as the 24 VAC to the TH terminal remains on

4. Within a fraction of a second after the pilot lights, the spark should shut off.

5. The main burner gas should turn on and stay on as long as the TH terminal is energized.


Could be a lack of sufficient gas pressure to operate the main burner.

That is, when the ignition control energizes thegas valve main burner, the gas pressure drops to zero, shutting off the pilot and causing the ignition cycle to recommence.

So check to see if the main burner control is being energized and then shuts off.
 
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Old 02-11-13, 03:17 PM
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Quick question pioneer, want to make sure I do this check right as my electrical knowledge is a bit rusty..I check the voltage with the volt ohm across the terminal on the module and the ground (common?) on the module? I don't want to fry any of the solid state stuff that might be in there
Thanks for sharing your knowledge. It is appreciated!
 
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Old 02-11-13, 05:26 PM
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Pioneer, I see a MV, MV/PV, PV, GRD, 24 VOLT, ALARM 1, ALARM2, E-COM, SENSE, SPARK, but no TH. Is this shorthand for another or one of the above terminals. Which of these do I check for the 24 volt across. Did you mean PV and not TH, or just across the 24 volt and ground? Thanks.
 
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Old 02-11-13, 05:58 PM
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Heil horizontal furnace problem

Pioneer-update as I was looking at a diagram for the previous post. I don not have Alarm 1 nor Alarm 2. There is a space for TH-W but it is blank and unocuppied and says on the module TH-W optional. Sorry for the confusion.
 
 

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