Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 5 of 5

Thread: Heater head loss?

  1. Back To Top    #1

    Join Date
    Oct 2010
    Location
    Friendswood, TX (near Houston)
    Posts
    65

    Heater head loss?

    I have been trying to find out what the approximate heater head loss will be for our pool build and have not been able to find good numbers anywhere.

    It is a Pentair Mastertemp 400 - I guess very common heater these days....

    A Pentair support guy told me it would about 13 ft of head at 30 gpm just for the heater
    He also said the head loss would be 14 ft of head @ 50 gpm. That sounds very strange to me

    Based on mas985 estimate and other trustworthy information, I had expected the head loss over the entire system to be <6 ft of head @ 30 gpm.

    I am getting a manual bypass over the heater which certainly seems like a good idea if it truly has 13 ft of head @ 30 gpm....

    Does anybody have better data?
    22000 gallon IGP, 820 sqft, SWG - IC60, infinity edge spa, Pentair Quad DE 100, 3 x Pentair Intelliflow 4x160 pumps (one for circulation + one for spa + one for sheer descents), spa with 8 jets + 4 leg jets, air blower, Pentair EasyTouch 8 remote, Pentair Intellibrites LED (white) - 2 in pool and 1 in spa, Pentair Master Temp 400,000 btu heater, 4 sheer descents (2x2', 2x6'), limestone coping and decking, Pebblesheen Prism Blue

    Useful links:
    Pool Chemistry
    Chlorine reactions

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Heater head loss?

    How did you come up with <6 feet of head?
    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

  3. Back To Top    #3
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,473

    Re: Heater head loss?

    It is really tough to find any data on heaters. I asked Hayward about mine and they gave me 3.25 PSI (7.5') @ 60 GPM. This is about twice what a cartridge filter would produce so I am thinking it isn't too far off.

    The head loss in pool plumbing is mainly determined by equipment, valves and fittings. Straight pipe has a minimal impact on overall head loss unless there are extremely long runs. Anyway, because of this, you can use a simple formula to model entire plumbing systems and/or any single piece of plumbing including heaters:

    Head Loss (ft) = Hf * GPM^2

    For entire plumbing systems, the CEC has defined Hf (head factor) as:

    CurveA -> Hf = 0.0167
    CurveB -> Hf = 0.05
    CurveC -> Hf = 0.0082

    The above numbers are for entire plumbing systems but the same methodology can be used for a single component. Here are some of the values that I tend to use for various pieces of equipment:

    Heater -> Hf = 0.002
    Cart Filter -> Hf = 0.001
    Skimmer -> Hf = 0.001
    SWG -> Hf = 0.0001

    According to Pentair's numbers, Hf would be 0.0144 for just the heater which is more than an entire plumbing system for CEC CurveC so I don't think that can be correct. 14' @ 50 GPM Hf would be 0.0056 which is still pretty large and would be a majority of CurveC head loss so I don't think thats very close either. What I have found with customer support is that it is hit or miss and sometimes you have to ask several times before you get someone who actually has a clue.

    BTW for CurveC which would be typical of a plumbing system with 2" pipe and single runs, here are the corresponding head loss values for various GPM values:

    30 GPM -> 7.4'
    40 GPM -> 13.1'
    50 GPM -> 20.5'
    60 GPM -> 29.5'
    70 GPM -> 40.2'
    80 GPM -> 52.5'
    90 GPM -> 66.4'
    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

  4. Back To Top    #4

    Join Date
    Oct 2010
    Location
    Friendswood, TX (near Houston)
    Posts
    65

    Re: Heater head loss?

    Mark,
    I guess you answered both Jason's question and mine in one post
    Since I have 2 and 2.5" plumbing and separate runs I would think the 6 ft of head @ 30 gpm sounds realistic.
    Do you know how a DE filter compares to a cartridge filter? I would expect it to be higher since it has finer filtering and lower flow area - both leading to higher head loss.
    Actually Pentair has a curve of the head loss over the Quad DE 100 filter. Maybe I will just assume that the heater is comparable to that?
    22000 gallon IGP, 820 sqft, SWG - IC60, infinity edge spa, Pentair Quad DE 100, 3 x Pentair Intelliflow 4x160 pumps (one for circulation + one for spa + one for sheer descents), spa with 8 jets + 4 leg jets, air blower, Pentair EasyTouch 8 remote, Pentair Intellibrites LED (white) - 2 in pool and 1 in spa, Pentair Master Temp 400,000 btu heater, 4 sheer descents (2x2', 2x6'), limestone coping and decking, Pebblesheen Prism Blue

    Useful links:
    Pool Chemistry
    Chlorine reactions

  5. Back To Top    #5
    mas985's Avatar
    Join Date
    May 2007
    Location
    Pleasanton, CA
    Posts
    11,473

    Re: Heater head loss?

    Yes, 6' @ 30 GPM is realistic and would have a plumbing curve Hf of 0.0067 which is close to my plumbing.

    DE filters usually have higher head loss than a cartridge but it depends on the type of backwash valve. Pentair filters will usually have a pressure loss curve included with the filter manual. They also have the losses for the backwash valves if it is not included in the manual.
    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

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •