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

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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.



  1. 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?

    1. Author

      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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