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Thread: 250k btu heater big enough for 33k gallon pool?

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    250k btu heater big enough for 33k gallon pool?

    I have approx. 28000 gallon pool (L shaped, 40-18 long and 26-14 short, there is overlap there). I have a 250k but Hayward natural gas heater. I can't seem to get the pool above 75... the pool and heater are brand new and it seems there is something preventing the heater from going above 75 but I'm not sure what that would be, the heater is running. It is about 65 degrees outside and somewhat humid (live in southeast VA).

    Is the heater just not big enough?

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    Re: 250k btu heater big enough for 33k gallon pool?

    First, if the heater and pool are new, you have a warranty hopefully. Get the builder or their service company back out to look at the heater. Maybe you don't have the temp setting on the heater set to your desired temp. Also consider a thermal blanket for the pool to keep it warm during the cool nights. This way you will not lose any heat put into the water when the heater is on. As for the size, it should take care of the pool but would take a bit longer to heat to desired temp. If you had the larger 400K unit it would be faster to heat the pool.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: 250k btu heater big enough for 33k gallon pool?

    BTU of heater rule of thumb, more BTU equal faster heat-up. As what ps0303 said. Check your temperature settings, observe the operation. If the heater has an issue and cycles on/off every 5 minutes that could be why the temp never gets over 75. If you have an automatic controller you need to max the temp. settings on the heater to 104 degrees as the controller will stop the heater at your designated set temp but the heater wont heat past what he's set to.

    GL!

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    Re: 250k btu heater big enough for 33k gallon pool?

    We have a 400k BTU gas heater on our 30k gallon pool. It's older and less efficient so we're thinking about replacing it with another 400k. I just don't think a 250k will give you a quick enough response time. All told you'd be putting in roughly the same amount of energy (400k for shorter period vs 250k for longer) so for the relatively minor cost differential it's probably worth the initial expenditure to get a better "quality of life" experience - or so my wife reminds me daily.
    Geebot
    Chicago, IL
    30K gal, InGround Plaster Finish, 3.5'-9.5', Maytronics S300 Cleaner

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    Re: 250k btu heater big enough for 33k gallon pool?

    The temp setting on the remote/wall unit (aquaPlus) is 92. I had it before at 85 and it still stopped at 75. It stops at 75 now (set at 92).

    When the pump came on this morning, for example, the water temp was 65. The temp went up to 75 within two hours, so I'm not sure it's a size issue.

    To me, it seems that there is either some temperature-lock setting (the default on this heater is suppose to be 90) or maybe a faulty temp sensor? Is it possible it's not getting enough gas? I would think that would spring an error.

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    Re: 250k btu heater big enough for 33k gallon pool?

    Quote Originally Posted by ps0303 View Post
    First, if the heater and pool are new, you have a warranty hopefully. Get the builder or their service company back out to look at the heater. Maybe you don't have the temp setting on the heater set to your desired temp. Also consider a thermal blanket for the pool to keep it warm during the cool nights. This way you will not lose any heat put into the water when the heater is on. As for the size, it should take care of the pool but would take a bit longer to heat to desired temp. If you had the larger 400K unit it would be faster to heat the pool.
    Just so I know, a thermal blanket just sits on top of the water and is not anchored, so it is easily removed/applied?

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    Re: 250k btu heater big enough for 33k gallon pool?

    The reality is that at 28000 gallons that heater should return you about 1 deg/hr of heat rise. This is under ideal conditions such that you do not have heat loss due to cold air. I just looked at the air temps for Richmond and see that the overnight temps are in the low 40's, you are really at the limit for what that heater can do for you if you do not have a cover. Even with a cover, trying to add 1 deg of heat per hour may be futile at those low overnight temps
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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    borjis's Avatar
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    Re: 250k btu heater big enough for 33k gallon pool?

    Yes it just sits on the water bubble side down.

    No need for fancy thick 12 mil ones either, get the cheapest 8 mil one you can find, they
    all last 2-3 years at most.

    I'll share that I just bought one yesterday off ebay, it was $ 40 cheaper than buying it
    from their website (the company selling it) direct and free shipping too.
    16x32 IG Vinyl, 13,000 Gals. Hayward S-244T sand filter, SP2810X15 pump
    (1.5 HP motor) Raypak PR266AEN (266k btu) gas heater. TF-100 Test Kit.
    Dolphin E10 Cleaning Robot.

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    Re: 250k btu heater big enough for 33k gallon pool?

    Quote Originally Posted by ryta1203 View Post
    Just so I know, a thermal blanket just sits on top of the water and is not anchored, so it is easily removed/applied?
    While a thermal blanket makes sense, putting it on and taking it off is a 2-person job and then you either need a reel to keep it on or find a (non-unsightly) way to store when not in use. It's one of those things that's great in a perfect world but stops being used regularly in the real world.
    Geebot
    Chicago, IL
    30K gal, InGround Plaster Finish, 3.5'-9.5', Maytronics S300 Cleaner

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    Re: 250k btu heater big enough for 33k gallon pool?

    It's low 50s here at night, Richmond temps are close but ours are slightly more mild since I'm 10 minutes off the coast.

    I called Hayward, he told me to take the heater out of remote (put it in manual) and we set the temp to 90, so if I go out and check the heater and the water is still at 75 then there's a problem with the heater, he said otherwise it was most likely the water temp sensor in the plumbing (the one the remote is using to gauge).

    I also wonder if I could by a few smaller thermal blankets and put them next together, this would make for easier storage. Also, it's going to be hard to find one shaped for an L-shaped pool with a walkout.

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    mas985's Avatar
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    Re: 250k btu heater big enough for 33k gallon pool?

    If the heater is shutting off at 75F but set higher, there is something wrong with the heater. Also, do you have a VS pump and are you operating it at low speeds when using the heater?

    Yes you can cut the cover up into pieces. This is what I did to make removing the cover easier: DIY Solar Cover Roller
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    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: 250k btu heater big enough for 33k gallon pool?

    Well, it looks like something is wrong with the temp sensor. The heater is acting 'more normal' in manual mode (opposed to bypass operation), I'm getting more along the lines of 1 degree/hr as suggested by danpik, the temp on the heater is reading 71 and the temp on the remote (temp sensor on plumbing) is reading 75, so something is not right with the temp sensor reading. Going to continue to let heater run, will check again in a few hours.


    Yes, I'm running the pump on high. The heater won't turn on if the pump is in low speed, there is not enough flow.

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    mas985's Avatar
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    Re: 250k btu heater big enough for 33k gallon pool?

    They didn't put the temp sensor after the heater did they?
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    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: 250k btu heater big enough for 33k gallon pool?

    Quote Originally Posted by mas985 View Post
    They didn't put the temp sensor after the heater did they?
    No, looks like it just might be a faulty sensor.

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    Re: 250k btu heater big enough for 33k gallon pool?

    is the heater plumed up properly? Inlet, outlet connected properly?
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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    Re: 250k btu heater big enough for 33k gallon pool?

    Quote Originally Posted by danpik View Post
    is the heater plumed up properly? Inlet, outlet connected properly?
    Yes, the heater is working fine. When I turned the gas heater to manual mode (ie, not bypass operation) everything seemed to work ok, with it being only 250 (wish we had installed a 400, considering they aren't much more expensive) it gets about a degree every 90 minutes.

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