Ya'll
Older furnace with standing pilot. Yesterday I cleaned the flame rectifier it is still in pretty rough condition , pilot lite fine. Today called back, pilot out again.......
I'm going to take more time with this one tomorrow and actually measure amps and look at flame/rectifier engagement. While cleaning the rectifier appeared to be far away from flame, maybe only top 1/4" actually getting hit with flames and on angle away from flame instead of leaning towards flame.
Questions;
What's good micro amp reading? 1-4 uamps?
How important is the flame engagement with rod? should it be almost totally engulfed in flames?
Think I should put in a new one but would like to get readings first.
Thanks guys
Bob
On a standing pilot, there is no flame rectifier. It will have a thermocouple. They don't last forever and you said it looks pretty rough. It sounds like you need a new one. They are less than $20. A working thermocouple measures 15-30 millivolts DC.
Thanks
I'll put on my thermocouple adapter and measure millivolt consistency with full expectations in putting new one in..
Was only getting 5-7 mv with pilot on. I took it out and bench tested it comparing to a new one. Both reacted same with direct heat, no problem getting up to 40mv+ when red hot. I'm going to put old one back in and adjust bracket position to get more direct flame engagement.
Question - how was the gas valve staying on when thermocouple was only reading 5mv?
Thanks
2 to 5mv can keep the pilot coil open.
Disconnect your pilot tubing and smack the pilot hood with a wrench while you blow through the tube. That usually cleans out the orifice and gives you a nice strong pilot. Otherwise look at increasing the pilot pressure to give you a nice flame. Usually there is an adjustment screw on the gas valve, beside the pilot tube port.