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Thread: heat time

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    heat time

    I am heating my pool for a party today. I turned it on last night at 2am. The outside temp is 60 and the pool water was about the same. I wanted to heat the pool to about 83.
    Question, my Jandy LXI 4000 has a "pool heat" and "spa heat" button. I put it on "pool heat" and after 5 hours the water temp is now 73. If I push the "spa heat" button, does that give a faster heat or is it the same as "pool heat"?

    I have manual valves so they are set to pool. Are both setting the same amount of heat?
    25,000 gallon freeform inground gunite pool with 12" raised spa. 3.5'- 6.4' deep.
    2 skimmers, 6 returns and bubbler on sunshelf.
    Jandy 1.5 hp pump, Jandy valves, Jandy CL340 cart filter, Jandy Aquapure 1400 SWG, Polaris 280 w booster, Jandy LXI 4000 heater.
    White plaster, flagstone coping, custom tan tiles with decos on raised spa.
    Pentair lights.
    650 sq ft concrete deck.

  2. Back To Top    #2
    spishex's Avatar
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    Re: heat time

    Quote Originally Posted by gregg123
    Are both settings the same amount of heat?
    Yes, it just allows you to have two thermostat settings so you don't have to constantly dial up and down when switching between the two. Like memory presets on your radio.

    *Just to be clear what the 'yes' was answering

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    JasonLion's Avatar
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    Re: heat time

    I think spishex miswrote. Pool mode and spa mode will both heat at the same rate. The two different modes simply give you two different final temperature settings, like presets on a car radio. The heater always runs at it's maximum heating rate when the water is colder than the current target temperature.

    It takes a tremendous amount of heat to heat a pool. Pool heaters are frequently several times the size of the furnace that heats a single family home. You are getting almost 3 degrees an hour, which is fairly good. I would guess that you have another four or five hours to go.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: heat time

    While heating the pool I had a thought. Rather than running the cooler bottom of the pool water through the heater then out the returns why not heat the spa to a 100+ and let that spill over into the pool. By the time the heated water from the returns make it out a few feet they have cooled off. If you have all that concentrated hot water pouring in the pool, wouldnt that heat it faster? Any thoughts?
    25,000 gallon freeform inground gunite pool with 12" raised spa. 3.5'- 6.4' deep.
    2 skimmers, 6 returns and bubbler on sunshelf.
    Jandy 1.5 hp pump, Jandy valves, Jandy CL340 cart filter, Jandy Aquapure 1400 SWG, Polaris 280 w booster, Jandy LXI 4000 heater.
    White plaster, flagstone coping, custom tan tiles with decos on raised spa.
    Pentair lights.
    650 sq ft concrete deck.

  5. Back To Top    #5
    JasonLion's Avatar
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    Re: heat time

    No that won't help. The heater is most efficient when it is heating very cold water by just a couple of degrees, so drawing cold water from the main drain is the ideal setup. Also, you would also lose heat to the environment more quickly from the spa while it was at the higher temperature.

    Heat is produced by the heater at a more or less uniform rate, typically somewhere between 100,000 and 400,000 BTUs per hour (depending on the heater). Each BTU can raise 1 pound of water 1 degree. A gallon of water is about 8 pounds. That means that it takes about 80,000 BTU to raise 10,000 gallons of water by one degree.

    You have 25,000 gallons and were trying to raise the water temperature by 23 degrees, which means you needed about 4,600,000 BTUs. Actually you needed significantly more than that, since heaters are not perfectly efficient and heat is lost from the pool to the environment all the time. In practice it could easily have taken 6,000,000 BTUs. A 400,000 BTU heater (a large heater) would take 15 hours to produce that much heat. So really you were doing very well.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Join Date
    Apr 2007
    Location
    Central Florida
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    84

    Re: heat time

    Here's an example of my heat time for our pool party this past weekend
    We have a Starite Max-E Glass 400K BT. Temperature of pool 16K gal. pool was 59 degrees with a solar cover on. We started heating the pool at 2am and it arrived at our set heated temperature of 84 degrees at noon. In a nut shell it took 10hrs to heat it 25 degrees. Solar cover cover was in place during the warm up too. Propane reading at start was 78% after heat it was 30%, expensive swim day...
    HTH

    JasonLion that was great information, I wish I had this information a few weeks ago.
    18k free form IG w/spa (4 jets), Paramount in floor cleaning system, Starite system 3 filter, Jandy 2hp ePump, Sta-Rite SR400LP Maxi-therm propane heater, Jandy aquapure/apurem 1400 SWCG, Jandy automation PS4 w/PDA, IntelliBrite 120v 5-G LED pool & spa lights, 2" piping and (3)4x12 (5)4x10 Fafco Sunsaver Solar Panels.

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    launboy's Avatar
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    Jun 2008
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    Re: heat time

    Quote Originally Posted by towney
    Propane reading at start was 78% after heat it was 30%, expensive swim day...
    Yeah, expensive, how big is your tank?

    Adam
    18' x 42" Intex Easyset Pool, with 16' x 52" deep end in the middle. Approx. 5500 Gal.
    Hayward Power-Flo LX 1 HP, 100# Jacuzzi Brand Sand Filter(Piped underground so it looks nice) 8)
    3 - 2' x 20' Solar Pool Heater Panels(roof mounted)
    Goin' on 9 summers...NOBODY thought it would last this long.
    Buried Portable Spa sharing pumps and water with pool (Almost complete project)

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    mitch08's Avatar
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    Jun 2008
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    Re: heat time

    Between 2 and 3 degrees an hour is very impressive.
    I would be thrilled if I were you.

    My IGP gets about a degree per hour if I am lucky. And I can't really complain about that cause it gets there as long as I time things right.

    Does your heater have a digital thermostat? If not, it is possible to rig it up with a digital "refrigerator" thermostat. You can then set the temperature to a specific degree. Once it gets there, your pool temperature will stay consistant and probably cost you much less in the long run since it doesn't have to heat the pool over 20 degrees in one shot.

    Just make sure you have a firemans switch.
    18x38 Inground Liner (25k gal) Paver surround, multi-speed pump, DE Filter, Raised spill over spa, TF-100

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    Join Date
    Jun 2008
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    Bruce Peninsula - Ontario
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    Re: heat time

    Propane reading at start was 78% after heat it was 30%, expensive swim day...
    HTH
    How big is that propane tank?
    20 X 40, 28000 gal IG cement bottom, steel sides, vinyl liner, Pentair 4X160 pump, sand filter, SWG, Titan heat pump, coluorlogic and fiber optic. concrete-exposed aggregate deck
    1 skimmer, main drain, 4 returns ( 2 in stairs ) JEWEL LIKE WATER thanks to TFP!

  10. Back To Top    #10

    Re: heat time

    We've noticed that heating our 20x40 pool from full cold (60ish) to 75+ takes most of a day. That's with the natural gas heater running all that time. Our gas bill goes up around +$200 for that month, then levels back down to +$100 or so if we keep it at 70ish and 78ish Friday-Sunday.

    We keep a solar cover on most of the time.
    - Reji

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    frustratedpoolmom's Avatar
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    SWSuburban Chicago, IL
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    Re: heat time

    Quote Originally Posted by Piney
    We've noticed that heating our 20x40 pool from full cold (60ish) to 75+ takes most of a day. That's with the natural gas heater running all that time. Our gas bill goes up around +$200 for that month, then levels back down to +$100 or so if we keep it at 70ish and 78ish Friday-Sunday.

    We keep a solar cover on most of the time.
    Where are you located?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: heat time

    East of Houston
    - Reji

  13. Back To Top    #13

    Join Date
    Jul 2007
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    Sahuarita, AZ
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    278

    Re: heat time

    3 degrees an hour is about what I get too... Mine is hooked to our natural gas and I've been extremely surprised by how cheap it is to operate... several times over the winter I heated the pool from 50ish to 80ish on weekends where we had warm weather... I would just turn the heater on the night before and it'd be warm the next morning. I've never seen my bill increase by more than about $30 though... Keep in mind, I didn't leave the heater running all weekend, usually just to heat it up initially, and then a few hours Sunday morning to re-capture what was lost overnight. A buddy of mine thinks my gas meter is broken.
    My Pool:
    12K gal IG gunite with 7' raised spa, gunite waterfall, PebbleTec Caribbean Blue finish, solar heating & in-floor cleaning system

    Equipment: Sta-Rite 300' Cartridge Filter, Intellichlor IC20 SWCG, Sta-Rite 400k BTU heater, Intelliflow 4x160 main pump & Sta-Rite 3/4 hp waterfall pump, EasyTouch controlls w/ wireless controller, TF-100 Test Kit w/ salt test.

  14. Back To Top    #14

    Join Date
    Mar 2009
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    eastern washington state
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    275

    Re: heat time

    i have a heat pump for my pool, its the most economical way to heat a pool if your not in hurry,
    we are in Washington state where electricity is pretty cheap.
    live in eastern washington state
    18x36, Vinyl inground 24k
    Hayward 1 hp filter pump
    1 skimmer/2 returns
    24" sand filter, polaris 280 with booster pump.

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