Hi guys, I have been amazed with the knowledge here. I have typically been able to find answers by looking long enough but I am stumped. Rather than give you a long drawn out story, I will try to hit the sequence of events in bullet style.
-Heater blower was struggling to provide enough speed to satisfy the vac. switch. The heater would light after purge cycle but wouldn't run long. Motor was very hot.
-Heater ran perfectly until February 2011
-Attempted to run heater while experiencing a cold front that put Houston temps into the 30s.
-Heater would light but would only run for 2-3 minutes before going into a cool down cycle.
-Once cool down was complete, the heater would immediately ignite and run again for 2-3 minutes.
-Placed controls in service mode (to rule out something wrong with temperature/thermister and call for heat)
-Heater still cycling short heat cycles
-Pulled panel door, tapped gas valve, pressure switch and some other general fumbling around.
-Heater ignited and ran for ~15 minutes.
-Control panel breaker providing service to heater tripped.
-Sub panel providing power to control panel breaker tripped.
-Re-set breakers and attempted restart - No Dice
-Pulled heater cover to check for burns or smoke Neither
-Checked resistance across blower leads ~130 Ohms (tech manual for the IDLII called for 8-9 ohms.)
-Installed new blower, again, no dice
-Checked pressure switch continuity while pumping water - fine
-Checked continuity to verify vac switch was verified open when heater gets call for heat
So, that is where I am, I am guessing that I am looking at an issue with the control module. I guess I will have to try to see if the blower is getting any power.
Any other thoughts?
Thanks in advance.