Solar Pool Heating Problem – Bubbles in the Pool (Video)

The following video explains a very common issue reported with solar pool heating systems. Solar pool heaters rely on adequate flow for proper operation. If the flow rate gets too low, air is let into the system through the vacuum relief valve, which allows air into the panels when a vacuum exists to protect the panels and plumbing from collapsing. The resolution is usually as simple as cleaning or replacing your filter cartridge. A dirty filter increases pressure on the pump, decreasing flow, and stops the vacuum relief valve from closing completely. Air gets into the system, reducing performance and causing bubbles in the pool.


  • Comment (4)
  • Kevin J Belfry says:
    Your comment is awaiting moderation. This is a preview; your comment will be visible after it has been approved.
    Will do thank you
  • I have a new 1 hp motor filter clean have 12 lbs of pressure but getting small bubbles when solar panels are turned on? The panels are about 8 Feet from pump 1 story house panels are also brand new the motor and pump brand new went from a 1.25 hp motor

    • Jason Szumlanski says:

      Hi Kevin,

      Without knowing the full dynamics of your pool and solar panel system, it’s impossible to determine what’s going on. But going to pump with a lower HP rating is concerning. On the other hand, it could be unrelated. It could be something as simple as your pump impeller is clogged. But most likely you are just not pushing enough water through the panels now with a smaller pump. The flow rate is not high enough to create enough pressure to close the vacuum relief valve. That would be my guess with the limited information.

      It’s time to get a local pro involved.


  • Jeremy Schaefer says:

    My glass filter is clean. We have a new high quality VRV. Our variable speed pump is set at 40gpm so filter cleanliness isn’t ever an issue anyway since the pump will ramp up to ensure flow.

    We have bubbles. The only way it seems to get rid of them is if I close the ball valve on the return line to 50% or slightly more.

    What is the issue?

    • Jason Szumlanski says:

      Hi Jeremy,

      More information is needed. There are so many factors. System pressures, VRV type (I don’t know what “high quality” means exactly), number of panels, size of panels, type of panels, plumbing size, roof height, etc. These all interact with your existing pool plumbing. You may just need more flow (higher pressure in the panels). Depending on your pool, it may require relocation of the VRV. This is something a solar pro needs to assess on-site, but it typically just means your flow rate is not sufficient for one reason or another.

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