Hayward H150 heater not firing

[dorn4ever]

This may be an easy question for someone that's had the issue before. I have an older Hayward H150 millivolt natural gas heater that will not fire up. The pilot is lit and looks like a good flame. I'm getting about 390 mv throughout the safeties and back to the gas valve. Is 390 sufficient to open the gas valve meaning the gas valve needs replacing? Or is 390 too low and the thermopile needs replacing? Both the pilot assembly and gas valve are only 2-3 years old though I know they can go bad quickly. Thanks for any help!

 

[ajw22]

390 mv should be good enough to run the heater.

@swamprat69 @1poolman1 may be able to help more.

 

[1poolman1]

All schools I attended recommended nothing less than 450.

 

[dorn4ever]

Thanks. Going to try and clean the pilot orifice and all the connections to see if that helps.