New Heater Question


Mar 15, 2019
I'm not seeing any benefit w/ the more complex electronic controls ... especially units with forced combustion .... are they just for the low nox? Thinking of ordering the simple RayPac 400k BTU millivolt ... what am I missing? I don's see an ASME version of the Millivolt.

Have been nursing along my old 400k BTU Mini Max now for a couple of years .... it's an ASME millivolt natural gas unit. Pushing 25 years old. A few years back I was going to replace it but , took it apart to clean/descaled the Heat Exchanger. Last year the gas valve on off knob is starting to stick ... and it's just rusting away. The efficiency did increase after cleaning ... but, it seems weaker vs years ago.

It seems some of the new models just add electronic ignition w/ digital controls while others go even further with forced combustion ... most get lower reviews and they still only have 85% efficiency.

I do worry about the standard possible thinner copper heat exchanger. I have an old school concrete 20x40 pool -- Chlorine/ sand filter


Well-known member
Jul 30, 2013
Long Island, NY
I have the Raypak mV version and it does the job. Had an intermittent issue with the thermostat causing issues with the safety circuit continuity, so I just bypassed it. One downside to the mV is that the pilot burner advertises the heater as an inviting cozy lodge for small furry critters on cold nights.
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