Wiring Pentair 150M natural gas heater- HELP!

Tommy V · Jun 17, 2020

Ok, so I bought a used Pentair 150M heater and the previous owner removed the transformer. I bought a new transformer and connected the two spade connectors to my two incoming black & white wires. I’ve twisted the black & black/white together and the red, red/white together per the instructions I’ve read on-line. My question is - What do I hook those wires to? There are no open spade prongs on the control panel that I can see. Am I missing another part of some kind? I have power to the transformer, so I just need to know what to hook it to?
Thanks,
Signed, New Guy

swamprat69 · Jun 18, 2020

That appears to be a millivolt gas valve. Did you run the power supply to the heater?

swamprat69 · Jun 18, 2020

Photo of the front of the control panel and the pentair tag on the bottom left by the burner compartment would be helpful

Tommy V · Jun 18, 2020

Yes, it’s a millivolt system and I have a 110 circuit running to it (gray cord going into the side with one white and one black wire. Those wires are connected to the black, black/white and red, red/white wires on the transformer. My question is, what plugs into the two wires coming out of the other side of the transformer? Do they go somewhere inside the unit, the control board, or to somewhere else? Thanks in advance for any help you can offer.

swamprat69 · Jun 18, 2020

The idea behind a millivolt heater is that is does not need a power supply to it. Everything is run by the small amount of voltage generated by the pilot thermopile/powerpile. So there is no reason to have 110VAc supply or a transformer in the heater. The pilot is lit by putting the gas valve knob in the "pilot" position and pushing it down. Then you push the spark generator button to the right of the gas valve until the pilot lights. Continue to hold down the gas valve knob for 2-3 minutes. Then relrease the downward pressure on the gas valve knob. If the the pilot flame is a strong blue flame and the thermopile is good, the pilot flame should stay lit when you let up on the gas valve knob. Turn the gas valve knob to the "On" position. Push your rocker switch to "Pool" and adjust the temperature dial. The burner flames should also be strong and blue, but if the heater has been sitting a while you may get an orange coloration to the flames for the first couple minutes as disturbed dust inside the heater burns off.

ajw22 · Jun 18, 2020

Tommy, you have propane gas and not NG?

Tommy V · Jun 18, 2020

Thanks for the info Swamprat. I’ve never worked on one of these before, so I didn’t want to really screw something up. I will try to fire it up and see what happens...

AJW22 - it’s been changed to NG. Good eye though..

Tommy V · Jun 24, 2020

Hello again! Well, I had to replace the thermopile and pilot and I managed to get it fired up! Yay! Problem now is that it does not respond when I turn thermostat down or turn the power switch off. The only way to shut it off is by turning off the pump (at least I know the pressure switch is working). Any ideas? Control panel, maybe? Gas valve is brand new, so I know it’s not that.

JamesW · Jun 24, 2020

Sounds like the thermopile might be wired incorrectly.

Do you have a picture?

Tommy V · Jun 24, 2020

Not right this minute, but there’s only two wires (one red & one white) and I wired it exactly the way it was when I removed it (took a photo to make sure).

Tommy V · Jun 24, 2020

I guess I could switch them and see what happens?

JamesW · Jun 24, 2020

Tommy V said:
I guess I could switch them and see what happens?

Typically not a good idea.

Always be sure before you change things.

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Wiring Pentair 150M natural gas heater- HELP!

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