gepman
Electrical
- Mar 26, 2007
- 364
I am sitting in my house freezing while it is snowing and hailing outside. My furnace won't start. I have a Honeywell S8610U1003 ignition control unit. I have attached the installation manual for this unit.
I am not a serviceman and I was wondering if anyone else had experience with this ignition unit or other ignition cycles and could tell me how long the pilot valve is usually open before it shuts off due to lack of flame? I would like some other opinions before I order a new part (for some reason they always break down on the weekend). You can read on if you want to see exactly what I checked.
Yesterday when the weather was at least not raining or snowing I went on the roof to check the unit out. The spark is good, I get a tiny pilot flame, and then it goes out. I took out the igniter and checked the pilot orifice, it looked fine but I cleaned it anyway. I hooked up my Fluke and Amprobe to measure the voltage and current (see figure 2 of attachment). Voltage was fine at 28V across terminals TH-W and 24V GND even while attempting to light the pilot. Voltage at terminal PV would only pulse to about 20V for one reading (the digital display updates several times a second and I forgot to use the peak hold feature when I was up on the roof). When I jumpered between TH-W and PV during the start cycle (while I could hear the spark) the pilot starts and the main valve (MV) opens up almost immediately and the unit runs fine. I measured about 9 microamps from the flame sensor to terminal SENSE. When I pull the wire from the SENSE terminal the unit shuts down except of course if I have the jumper on the pilot valve stays open and then it keeps sparking.
So I am quite certain that the Honeywell S8610U1003 is faulty on the PV (pilot valve) terminal. My only question is how long does the PV (pilot valve) terminal remain energized before it shuts off due to no flame? It doesn't explicity state this in the installation manual although it could be inferred from Step 3 of the Figure 4 that it stays open 90 seconds but that seems to long and could result in gas buildup. If the PV terminal energizes for one to two seconds then I am quite sure the problem is the S8610U1003. If it is only supposed to energize for a pulse then the problem could be elsewhere (i.e. the flame sensor does not sense the flame fast enough although you would think that after the furnace was running I could then pull of the jumper and it would continue to run, which it does not).
I am not a serviceman and I was wondering if anyone else had experience with this ignition unit or other ignition cycles and could tell me how long the pilot valve is usually open before it shuts off due to lack of flame? I would like some other opinions before I order a new part (for some reason they always break down on the weekend). You can read on if you want to see exactly what I checked.
Yesterday when the weather was at least not raining or snowing I went on the roof to check the unit out. The spark is good, I get a tiny pilot flame, and then it goes out. I took out the igniter and checked the pilot orifice, it looked fine but I cleaned it anyway. I hooked up my Fluke and Amprobe to measure the voltage and current (see figure 2 of attachment). Voltage was fine at 28V across terminals TH-W and 24V GND even while attempting to light the pilot. Voltage at terminal PV would only pulse to about 20V for one reading (the digital display updates several times a second and I forgot to use the peak hold feature when I was up on the roof). When I jumpered between TH-W and PV during the start cycle (while I could hear the spark) the pilot starts and the main valve (MV) opens up almost immediately and the unit runs fine. I measured about 9 microamps from the flame sensor to terminal SENSE. When I pull the wire from the SENSE terminal the unit shuts down except of course if I have the jumper on the pilot valve stays open and then it keeps sparking.
So I am quite certain that the Honeywell S8610U1003 is faulty on the PV (pilot valve) terminal. My only question is how long does the PV (pilot valve) terminal remain energized before it shuts off due to no flame? It doesn't explicity state this in the installation manual although it could be inferred from Step 3 of the Figure 4 that it stays open 90 seconds but that seems to long and could result in gas buildup. If the PV terminal energizes for one to two seconds then I am quite sure the problem is the S8610U1003. If it is only supposed to energize for a pulse then the problem could be elsewhere (i.e. the flame sensor does not sense the flame fast enough although you would think that after the furnace was running I could then pull of the jumper and it would continue to run, which it does not).
