Dirty Pool Filters Cause Bubbles in Pool With Solar Pool Heating

One of the most common questions about solar pool heaters is why bubbles are sometimes seen in the pool. Air enters the pool circulation system and comes out of the jets into the pool. Why does this happen?

First, it's important to understand whether the air is coming from the solar pool heating system or elsewhere in the pool circulation system. Bypassing the solar panels (turning solar pool heating off) can help determine if the source is the solar pool heater. If bubbles go away with the system off, it is likely that air is entering the vacuum relief valve on the roof. Air enters this valve when there is not enough water flow in the system to close the valve. This can happen for a variety of reasons, including:

  • Your filter may be dirty. Even if you have recently cleaned your filter, fine particles may have accumulated, indicating it's time to replace the cartridge altogether. A filter that "looks" clean is not necessarily clean. You can check to see if a dirty cartridge is the culprit by running your pump with the cartridge removed and the filter housing reassembled. If the filter is too dirty, the bubbles will have stopped and the pressure gauge will have a substantially lower reading.
  • Running a suction cleaner can reduce the output pressure of the pump.
  • The pump is faulty or failing.
  • There is an obstruction in the suction or return plumbing that is causing the total system pressure (total dynamic head in technical terms) to be increased. Checking total dynamic head requires the use of vacuum and pressure valves on the pump and is best left to the pros.

If the solar pool heater is not the source of the air bubbles, you likely have a suction leak somewhere else in the plumbing. You can check the following:

  • Check the level of the water in your pool. Low water levels can allow the skimmer to suck air into the system.
  • A whirlpool effect in your skimmer basket may be drawing air into the system. This is more likely if the pool level is low.
  • Run a gentle stream of water from a hose over suction plumbing fittings and valves and see if the bubbles stop. You should see the bubbles reduced in the pump's filter basket.
  • The filter basket cover may be loose or the o-ring may be deteriorated. Again, running a gentle stream of water over the pump housing may reveal this.
  • Check that the bolts are tight between the pump housing and the pump motor. Air may enter the system at this junction. Again, running a gentle stream of water over the pump housing may reveal this.
  • Suction leaks can exist in plumbing that is not exposed (underground). Hiring a leak detection specialist may be required.

If these diagnostic steps do not solve the problem with bubbles in your pool with solar pool heating, call Fafco Solar at (239) 574-1500 and we will be happy to assist you.