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Thread: School me on gas heaters

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    School me on gas heaters

    I have a new 400K Jandy LXI heater and I'm not sure what type of "temperature rise over time" equates to "good" performance. Pool is about 22K gallons and I've turned it on for the first time this weekend. It seems to operate fine and is quieter than I thought it would be. Today I saw a rise in temp from 67 degrees to 80 degrees in about 6.5 hours. Is that slow?

    Also... how about efficiency? Is it cheaper to keep it at say 75 degrees (i'm on So Cal so this isn't out of the question) so when you do want to boost temp it doesn't have far to go? Or is it cheaper to let the pool cool down to the 60s and just start the heater when you want to swim? Maybe once a week this time of the year.

    Thanks!
    Shelley
    Denver, CO

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    JasonLion's Avatar
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    Re: School me on gas heaters

    Pools use tremendous amounts of heat. Going up 13 degrees in 6.5 hours is fast if anything.

    The best approach for efficiency very much depends on how you use the pool. If you swim every day then by all means keep it hot. But if you swim once a week it is less expensive to let it cool down for the rest of the week. Using a solar cover can make a dramatic difference in your heating expenses.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    mas985's Avatar
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    Re: School me on gas heaters

    A 13 degree rise in 6.5 hours is about 90% efficiency for a 400k BTU heater so I would say that is excellent performance.
    Mark
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    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: School me on gas heaters

    In theory, that 13 degree rise with 400k BTU input should have taken 5.9 hours. So your 6.5 hours shows about 90% efficiency. Thats pretty good. i get around 90% ith mine too. The newer heaters are actually very efficient.
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

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    Re: School me on gas heaters

    The Jandy LXi is rated at 88 % efficiency, which is very good, so what you're seeing is about right. The Hi-E2 is rated at 95 %, which is excellent. The older models are typically about 81 to 84 % efficient.

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    Re: School me on gas heaters

    Perfect. Thanks all!
    Shelley
    Denver, CO

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