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Thread: Pump and Solar Panels Question

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    Pump and Solar Panels Question

    Hey,
    This is a very informational forum.. I have a question on the pump and solar panels. I hope some one can help. I have had 2 2x20ft panels up on my roof for 2 years now and I this past week end added 2 more. I put them in series with the other 2. I have a 1hp pump and I'm about 20 ft away from the house with about a 3 ft drop down to the pool from the house. I have the panels up 1 story
    on the roof. Most of my plumbing is 1 1/2 pvc. The connections to and from the panels are the clear hose 1 1/4 with the nylon embedded in it. My problem currently is on the last panel the hose connection is starting to suck close not completely but over half way. If I crack the hose clamp there I can hear is suck air along with the water going past. Is this a problem? Pump pressure looks about 18psi

    Thanks

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
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    Re: Pump and Solar Panels Question

    Welcome to TFP!

    I'd say it's a problem. The weight of the water going down is creating negative pressure on the panel which could damage it.

    You normally only do series connections on ground-level panels. It is ineffecient at heating and restricts water flow.
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    Mod Squad jblizzle's Avatar
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    Re: Pump and Solar Panels Question

    Welcome to TFP!!!

    Can you add a picture of the layout? Generally you get better flow if you run them all in parallel.

    So you are seeing the pipe collapse while the pump is running? That is odd, but could very well be to the way it is plumbed. Do you have a vacuum release valve in the system? That will prevent things from collapsing when the pump is off, but if this is occuring with the pump on, then there are other issues.

    Please add your pool details (specifically your pump model) and location as described HERE as it will help us help you.
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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    Quote Originally Posted by marks6x6
    The connections to and from the panels are the clear hose 1 1/4 with the nylon embedded in it.
    There's your problem. Nylon tubing is too flexible to support negative pressure and will collapse easily. However, most panels can support slightly negative pressure without collapsing. You might consider replacing the tubing with ridged PVC.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
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    Re: Pump and Solar Panels Question

    I cannot upload images but the panels are from www.smartpool.com and model s421p. connected the way they have in the instruction manual for 4 panels (including a bypass valve to bypass panels.)
    Some information I have been reading states they depend on some "vacuum" on the return line to help take the load off on the pump. I was thinking of removing the soft connections(hoses), and replacing them with pvc unions.
    As far as anyone can tell, the pump should be sufficient for this set up?

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    Mod Squad jblizzle's Avatar
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    Re: Pump and Solar Panels Question

    So you have 4 panels and it runs series through all of them like the "2 box" picture on page 4? That is VERY inefficient and would certainly change it so all panels are parallel. Problem is that is likely difficult depending on the layout on the roof.

    Why can't you post a picture?
    Jason, TFP Moderator
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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    What is the pump model?

    But yes, once the panels are primed, the downward weight of the water offsets the upward lift of the pump so the pump does not have to lift the water anymore. However, it sounds like you don't have a vacuum release valve so the panels remain primed all the time?
    Mark
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    Re: Pump and Solar Panels Question

    ]Hayward Power-Flo LX 1 hp. Not at home to get exact model number. I do not have a vacuum release. would vacuum release take away from helping the pump?
    When I click on insert image all I get is '' does not ask me to insert anything, no pop up blocker to worry about.

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    Mod Squad jblizzle's Avatar
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    Re: Pump and Solar Panels Question

    How are you trying to add an image? In the Full Editor?
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    Re: Pump and Solar Panels Question

    Got it... Lower part of screen .. didn't see " upload "

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    Re: Pump and Solar Panels Question

    I guessed incorrect on distance from the pool its about 30 ft underground and up 1 story.
    I disconnected the 4th panel and trying 3 panels. I also shortened the hose connection to 4in.
    I do not see as much of a problem and I'm pushing about 18psi at the pump. What if I dropped the return lines down to 1 1/4 to where they meet the underground lines would that help any?
    I attached some photos
    Attached Images Attached Images

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    Re: Pump and Solar Panels Question

    What type of vacuum relive valve would be used?

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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    The small pipe may be contributing to the problem by dropping the pressure at the panels so it may be better to keep the pipe as large and for as long as possible.

    Also, If any of the hose is collapsing, then you need to replace it with more ridged hose or pipe.

    I don't see the VRV in any of the pictures, where is it installed?
    Mark
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  14. Back To Top    #14

    Re: Pump and Solar Panels Question

    I do not have one installed, What type would you use?
    I guess I'm still learning about all of this but do you want to lose all of the vacuum on the return side? I thought this helps the pump out to pull the water up?
    Thanks for you patients, still trying to wrap my mind around this

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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    The reason to put a VRV in a solar panel installation is so the panels will self drain when the pump is off. There are two reasons you don't want water to remain in the panels when the pump is off. One is during cold weather when the panels could freeze. The second is during real hot weather when the water could get super heated and perhaps soften the PVC. When the pump turns on, it will re-prime the panels and the VRV will close.

    However, if the panels are sucking air while the pump is running, it means that there is too much pressure loss from the pump to the panels and if you put a VRV near the panels, they will not remain primed. So my question is, does the hose collapse just when the pump is off or when it is on as well?
    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: Pump and Solar Panels Question

    It was collapsing when on

  17. Back To Top    #17

    Re: Pump and Solar Panels Question

    when looking at this yesterday.. the fitting that is on the input side to the 1st solar panel looks like it dropped down to 1 in ID where I make the connection to the 1 1/2 PVC. If I make this an equal size connection (1/1/2 connection and take out elbow that drops to 1in that makes the hose connection) will that help ? You can see in the rooftop photo that I'm using 1 1/4 clear hose to make that connection.
    or is it I don't have enough pump to push it

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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    The biggest problem is that your pipe size is too small and the pressure the pump does generate is all lost by the time it reaches the roof so the panels are under a vacuum. You can make work the way it is now but it will require replacing the tubing with ridged pipe and placing the VRV on the supply pipe going up the house about half way up. It isn't ideal but I doubt you want to change all the pipe going to the roof.
    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

  19. Back To Top    #19

    Re: Pump and Solar Panels Question

    what would be a good size PVC pipe? 2"

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    mas985's Avatar
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    Re: Pump and Solar Panels Question

    Yes at least 2" but would you dig up all the pipe from the equipment to the panels? That is a lot of work. What is the pipe size underground?

    Also, can you post a picture of your equipment too? It looks like you have some flex pipe there as well and there may be some restrictions in that.
    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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