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Thread: DO I need a checkvalve to prevent back flow from solar panel

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    DO I need a checkvalve to prevent back flow from solar panel

    Hi, I'm installing a solar heating system to my pool. I have a 24' round Intex with a Hayward C50 DE filter. DO I really need a check vale between the filter and the inlet line for the panels? My panels are installed next to the pool and are about 3-4' higher than where the filter is. I do have a check valve installed on the output line for the panels but was wondering if the other one is really needed. I'm installing something similar to the system explained on the link below: http://rimstar.org/renewnrg/solar_pool_ ... mation.htm
    Looking at thhis diagram, I only need one check valve. Anybody care to comment?? Thanks!!
    Intex Ultra Frame 24' Round
    Sun-Heater 4'x20' Solar Heater
    Hayward EC-50 D.E Filter

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    JasonLion's Avatar
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    Re: DO I need a checkvalve to prevent back flow from solar p

    If the panels are mounted above the filter, and you have a vacuum release valve that allows them to drain down when the pump is off, and you have a DE filter, then yes you need a check valve after the filter.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: DO I need a checkvalve to prevent back flow from solar p

    Jason, yes the panels are about 3-4'the higher than the filter, but i do not have a vacuum relief valve. Is having the vac relief valve necessary?
    Intex Ultra Frame 24' Round
    Sun-Heater 4'x20' Solar Heater
    Hayward EC-50 D.E Filter

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    Mod Squad JohnT's Avatar
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    Re: DO I need a checkvalve to prevent back flow from solar p

    Quote Originally Posted by traxx2003
    Jason, yes the panels are about 3-4'the higher than the filter, but i do not have a vacuum relief valve. Is having the vac relief valve necessary?
    It is at the very least a good idea. Water left in the panels can get extremely hot, and the pull of gravity on the water can create negative pressure in the hot tubes causing them to collapse. The vacuum relief opens when the water is no longer under pressure, which allows the panels to drain.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    linen's Avatar
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    Re: DO I need a checkvalve to prevent back flow from solar p

    Which panels do you have?

    I do not have a vacuum release or a check valve on mine (sungrabbers) presently and have not had problems.

    My understanding of the having vacuum release valve is to allow the panels to drain when not in use. In addition, since your panels are not high above you pump there should not be any significant vacuum that could cause the small tubes to collapse.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: DO I need a checkvalve to prevent back flow from solar p

    I have the Sunheat by Smartpools, they are the 4x20'panels panels.
    Intex Ultra Frame 24' Round
    Sun-Heater 4'x20' Solar Heater
    Hayward EC-50 D.E Filter

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    linen's Avatar
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    Re: DO I need a checkvalve to prevent back flow from solar p

    It looks like the kits for those panels do come with a vacuum relief valve and check valve (should be installed on outlet from filter), so I would install them. The small tubes appear to be quite a bit larger than mine and less supported, so i would guess they may collapse due to vacuum more easily.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: DO I need a checkvalve to prevent back flow from solar p

    Really? My kit which I got from a friend, still sealed in the box did not included any vacuum relief valves. I did include the caps and pvc elbows to connect the two 2'x20' sections of collectors. I think I'm going to try them without the vacuum valves for now and see if I really need them. Specially since my panels are only 4' higher than my filter/pump and only about 2 feet away. I think I can get away without having to use one. We'll see.
    Intex Ultra Frame 24' Round
    Sun-Heater 4'x20' Solar Heater
    Hayward EC-50 D.E Filter

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    linen's Avatar
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    Re: DO I need a checkvalve to prevent back flow from solar p

    Could be that you got an add on kit, or maybe they have many versions of kits depending on vendor, etc.

    Quote Originally Posted by traxx2003
    I think I can get away without having to use one. We'll see.
    I would guess you can.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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