I have a Hayward H250 millivolt heater (natural gas), and the pilot won't stay lit when the button is released.
Two things I noticed:
1) The thermopile seems to be putting out very little voltage - when first lit it starts around 8mv, and after 2 minutes only reaches 18mv.
2) The pilot is a bright orange flame, like a candle, not blue as I suspect it should be.
I had a technician come out to do the initial install, and they claim the thermopile is fine, and that I actually have a faultly gas valve ($300+ part!). How can I argue with a professional, even if I took readings myself ?
Any advice ?