What should the flow rate be for my gas heater?

dmpizzle · Mar 15, 2014

We've decided to have a pool party in 24 hours, and my pool currently sits at 62 degrees. I'm turning on the gas heater now (Pentair MasterTemp) and just realized I have no idea how fast I should be pumping water through it. I checked the manual and it said 30GPM was the minimum. How do I know what's optimal?

Thanks for any help you can provide.

ps0303 · Mar 15, 2014

What size BTU heater is it, 250,000 or 400,000? Heaters have to have a minimum of the 30GPM or it will not fire. Also, What temperature are you trying to get the pool to?

dmpizzle · Mar 15, 2014

MasterTemp 300, which I believe is 300,000. Currently my flow rate is slightly above 30 GPM. I'm trying to get the pool to 80-82˚. Estimated pool size is 36,000 gallons. Air temp today and tomorrow will hit a high of 81˚.

ps0303 · Mar 16, 2014

You will get about 1 degree per hour of heat into the pool.

peterdaly · Mar 17, 2014

I believe generally you want the flow rate as high as possible for maximum energy transfer.

My knowledge is on the solar side, but I think the fundamentals in this case are the same.

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JasonLion · Mar 17, 2014

peterdaly, What you said applies to a solar panel, but it doesn't make very much difference in a typical gas pool heater. They normally regulate the flow through the heat exchanger internally to maintain it right around the optimum flow (and bypass the rest around the heat exchanger).

peterdaly · Mar 17, 2014

Interesting. Thank you Jason.

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