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Thread: Questions about Solar and PVC crush resistance

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    Questions about Solar and PVC crush resistance

    I just got a couple used solar panels off craig's list that are in decent shape. I am in the process of determining how I am going to plumb these and I am curious why a vacuum breaker would be required? If it is not present wouldn't the water just stay in the pipes and in the solar panels? Is the vacuum breaker an absolute must?

    Also, why wouldn't you want some water to stay in the panels some time? for example instead of running the pump all day long I've been thinking I may try running the pump for 5 minutes every hour or so to flush the warmer water out of the panels and replace it with cooler water. Is this not a good idea? If not then why isn't it?

    Also, does anybody happen to know the crush resistance of schedule 40 PVC? Once I mount the panels on top of my shed I will need to run the pipes under my driveway (just stone, not paved) and want to see if I can just direct bury the PCV (planning about about 1ft deep) or if I would need put put them inside of something.

    I'd be open to suggestions if anybody has any on preventing the pipes from getting crushed. I thought about getting 1/2 block cinder blocks and putting them in there or even pouring concrete, but both of those options seem like a real pain. I also thought about the schedule 40 gray conduit but I don't think that would gain me anything.

    All thoughts are appreciated.
    8200 Gal Vinyl 18' AG Vogue Pool
    150lb Hayward Sand filter with 1-1/2 HP Maxim Pump
    Intex SWG
    Some of the most helpful links for pool owners: Pool School | Pool Calculator | The best test kit | Chlorine/CYA chart

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    launboy's Avatar
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    Re: Questions about Solar and PVC crush resistance

    I don't have a vacuum breaker, yet, but I run my 3 panels all day long when the sun is out. The thing is, when you turn off the pump it creates a vacuum in the panels and if it's sunny the water can get so hot that the panels will begin to deform, or, so I've been told.

    If you're worried about crushing the PVC you could always test a couple of short pieces. Also, you could put the sections under the driveway in a steel pipe slightly larger then the PVC pipe.

    HTH,
    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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    Re: Questions about Solar and PVC crush resistance

    Quote Originally Posted by jugger2500
    I just got a couple used solar panels off craig's list that are in decent shape. I am in the process of determining how I am going to plumb these and I am curious why a vacuum breaker would be required? If it is not present wouldn't the water just stay in the pipes and in the solar panels? Is the vacuum breaker an absolute must?
    I'm thinking of solar panels. TN seems to have some pretty cold nights recently. My water is down to 74.
    Where can I find some info on purchasing, installation, use ......?
    Thanks
    12500 AGP 2HP Sand filter
    Five years on BBB & loving it!

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    mas985's Avatar
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    Re: Questions about Solar and PVC crush resistance

    If the panels are mounted on the ground, a vacuum release valve is not really necessary and may not even open depending on the height relative to the pool. However, if mounted on the roof or shed, it is a good idea to have a vacuum breaker to remove the water from the panels when the pump is not running for a couple of reasons.

    First, in winter, you really don't want any water in the panels that might freeze and it is much easier to have a vacuum breaker than it is to manually drain the panels.

    Second, in summer, you really don't water in the panels when the pump is off and during the day when it is hot. If the panels are on the roof, a significant vacuum in the panels will occur and could collapse the panel if the plastic gets too hot. This is especially true on a two story roof but less likely on a one story roof.

    Next, the heat transfer in the panels is proportional to the temperature difference of the water and the incident energy of the sun. So by letting the water heat up in the panels, you are actually reduce the heat transfer to the water. The maximum heat transfer is achieved by maximizing the water flow through the panels so the faster the water travels through the panels, the faster the pool will heat up. However, you don't want too much pressure in the panels either as that could also damage the panels so generally up to 60 GPM is sufficient to get maximum heat transfer.
    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: Questions about Solar and PVC crush resistance

    These guys sell solar heat components and Heliocol panels and have good DIY info on their site. They installed my 480sq ft setup ...
    Completed July 2008: 25,000 gal IG gunite, 3M "Smoke" Quartz, 6' sheer descent w/ fiberoptic light bar, 2 Hayward ColorLogic LED lights, IntelliFlo VF (running at 160 watts to filter - yeah !), Jandy PDA PS8, Jandy Aquapure 1400 SWCG (running at 15% :o) ), 8 "Jet Flow" returns, 450 sq ft Hayward cartridge filter, 480 sq ft HelioCol solar panels, Hayward VacAlert, Hayward Phantom Turbo, BBB method, TF-100 Test kit (of course !)

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    Re: Questions about Solar and PVC crush resistance

    pauster, I didn't see a company name, however am guessing you mean SolarSwim. If so, how did you like them, if not, who did you use? Thanks!
    Pool Details:
    - inground vinyl liner, approx 35,000 gal; Hayward DE-6000; Pentair VS3050
    - 600sq ft Heliocol; Blue Diamond; 8 Gal Liquidator
    - TF-100

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    Re: Questions about Solar and PVC crush resistance

    Pooltime,

    (odd - the url did not go through in my previous post)

    I used SolarSwim - solarswim dot net - to supply panels and install end-to-end. I had a challenge initially scheduling their installation (busy season I suppose) - but they eventually came out and did a fine job from all I can tell. They completed the job in 1 1/2 days, before the rest of the pool was done, so all is well.

    Please give my regards to Bob if you decide to work with him (tell him I was the one who sent the unfriendly fax)

    Patrick
    Completed July 2008: 25,000 gal IG gunite, 3M "Smoke" Quartz, 6' sheer descent w/ fiberoptic light bar, 2 Hayward ColorLogic LED lights, IntelliFlo VF (running at 160 watts to filter - yeah !), Jandy PDA PS8, Jandy Aquapure 1400 SWCG (running at 15% :o) ), 8 "Jet Flow" returns, 450 sq ft Hayward cartridge filter, 480 sq ft HelioCol solar panels, Hayward VacAlert, Hayward Phantom Turbo, BBB method, TF-100 Test kit (of course !)

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    Re: Questions about Solar and PVC crush resistance

    Patrick, how has the system worked for you thus far? We are trying to decide realistically how much heat gain we will get and if the cost is worth it.

    Thanks,
    Eric
    Pool Details:
    - inground vinyl liner, approx 35,000 gal; Hayward DE-6000; Pentair VS3050
    - 600sq ft Heliocol; Blue Diamond; 8 Gal Liquidator
    - TF-100

  9. Back To Top    #9

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    Re: Questions about Solar and PVC crush resistance

    It works great ! We can gain 3-8 deg F in a day although there are lots of tall trees around. It also cools the house so we don't need A/C. Very important to lengthen the short pool season in NJ.

    The pool get's 1/3 exposure to sun - and that only part of the day - and the roof faces mostly east and trees cast a partial shadow on the panles part of the day so conditions are not ideal, but under the circumstances I am very happy with the system. Our Jandy controller automates the whole thing. I set the pump to run at 40 gpm with solar and 30 gpm without. That's a tad under the manufacturer recommended 1 gpm / 10 sq ft of panels but close enough to the optimal point. Pump power consulmption increases from 160 watts to 620 watts but not running A/C saves much more electricity than the difference.

    We have too much heat loss at night right now so we have to figure something out. I don't want a solar cover and I can't have an automatic one with the shape of pool I have. A little concerned about using a solar pil and what it does to the pool chemistry.

    The whole system costs about as much as a good gas heater with installation so it's a great deal - and I just can't burn fossil fuel to have warmer water in the pool.
    Completed July 2008: 25,000 gal IG gunite, 3M "Smoke" Quartz, 6' sheer descent w/ fiberoptic light bar, 2 Hayward ColorLogic LED lights, IntelliFlo VF (running at 160 watts to filter - yeah !), Jandy PDA PS8, Jandy Aquapure 1400 SWCG (running at 15% :o) ), 8 "Jet Flow" returns, 450 sq ft Hayward cartridge filter, 480 sq ft HelioCol solar panels, Hayward VacAlert, Hayward Phantom Turbo, BBB method, TF-100 Test kit (of course !)

  10. Back To Top    #10

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    Re: Questions about Solar and PVC crush resistance

    Patrick:

    So far you have sold me, I will tell Bob he owes you some of his comission check What size system did you do vs the surface area of your pool?

    We face South and have full sun exposure from 11am or so until sunset with no real tree blockage so hopefully will benefit greatly.

    We were in the same boat as you as far as cover, we had an old solar cover which worked great, however it was too much for my wife to take off alone with our two small kids. We looked at differnet automatic covers, however becuase of the dimensions of our pool there was no where the tracks could go to keep under their maximum allowable width. We tried the solar fish liquid stuff for one season and agreed with the general idea here that they don't do too much good. We have actually had decent luck with solar sun rings; even after the cold nights and rain we had for the past week or so, we are still low to mid 80s in the pool. Ideally with the solar panels we can keep upper 80s.

    Can you give me some info on the Jandy control system you use, I would be interested to see if we could automate all of this once installed.

    Thanks,
    Eric
    Pool Details:
    - inground vinyl liner, approx 35,000 gal; Hayward DE-6000; Pentair VS3050
    - 600sq ft Heliocol; Blue Diamond; 8 Gal Liquidator
    - TF-100

  11. Back To Top    #11

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    Re: Questions about Solar and PVC crush resistance

    Hi Eric

    all in my signature - 750 sq ft free form, 480 sq ft solar as recommended by the installer. Sounds like such a system might work well for you - but for a 40K gal pool you may want to use more panels than I have to heat the water quickly - 600 - 800 sq ft I would say.

    It will take some pump power to move water through these panels to get them to work efficiently around here ...

    Patrick
    Completed July 2008: 25,000 gal IG gunite, 3M "Smoke" Quartz, 6' sheer descent w/ fiberoptic light bar, 2 Hayward ColorLogic LED lights, IntelliFlo VF (running at 160 watts to filter - yeah !), Jandy PDA PS8, Jandy Aquapure 1400 SWCG (running at 15% :o) ), 8 "Jet Flow" returns, 450 sq ft Hayward cartridge filter, 480 sq ft HelioCol solar panels, Hayward VacAlert, Hayward Phantom Turbo, BBB method, TF-100 Test kit (of course !)

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