This section covers some of the most common problems that can occur with pool equipment. It bears repeating that having a working filter gauge and knowing your clean filter pressure can be invaluable when diagnosing plumbing problems. So here are some of the most common plumbing problems and their symptoms:
Sudden decrease in filter pressure
This is often caused by a clogged suction line or clogged pump impeller but it can also caused by an improper valve setting.
Suction lines can sometimes be cleared by forcing water backwards through the pump suction line located inside the pump basket. Wrapping a rag around a hose and sealing it inside the pipe can force out the debris. Another useful tool is a Drain King available at many hardware stores which can help dislodge the debris.
To check for a clogged impeller, with the pump off, remove the pump basket and reach into the pump inlet at the bottom of the pump and try and remove any debris that may be there. For stubborn debris, it may be necessary to take apart the pump to remove the debris out of the impeller.
Sudden rise in filter pressure
An algae bloom may be clogging the filter even if you cannot tell there is algae. It is important to first kill the algae before doing anything else. Otherwise, you will be spending all your time cleaning the filter. See Pool School for suggestions.
Other causes of a spike in filter pressure are a broken check valve or improper valve setting.
Large reduction in flow rate
Higher than the normal filter pressure usually indicates a dirty filter which just requires cleaning the filter. However, lower than normal filter pressure can indicate a suction side clog which can be handled by one of the methods mentioned above.
After cleaning the filter, the filter pressure doesn’t decrease
For a DE filter, this can be caused by DE caking on the grids which requires a deep cleaning of the grids.
For a cartridge filter, this can be caused by calcification and requires first cleaning the cartridge with TSP and then soaking it in a water/acid solution per manufacture recommendations.
Debris is getting past the filter
For a DE filter, this can be caused by a damaged grid. Inspect and replace grids as needed.
For a cartridge filter, this can be caused by a damaged cartridge. Inspect and replace cartridges as needed
For a sand filter, this can be caused by channeling in the filter. First try a longer backwash cleaning.
Air bubbles coming out of the returns and/or in the pump basket or in the filter
If the bubbles coming out of the returns are tiny (champagne size) and you have an SWG, this is normal and part of the electrolysis process that creates chlorine. It is also normal for a pump to purge air out of the plumbing system at pump start up. However, if the bubbles are larger and continue for a long time, there could be a suction side air leak. Air leaks usually happen around the pump basket lid or the pump drain plugs. Silicon pool lube will usually help seal the gaskets to prevent leaking.
Pump leaking water
The pump shaft seal or other pump gasket may be leaking. Purchase a pump seal kit and replace all of the seals or have a professional do it.
Pump cycles on and off
The pump motor is probably overheating and the thermal limiter switch is shutting it off. Once the pump cools down, the motor switches back on. This is often caused by a bad motor bearing and normally will make a high screeching or squealing sound. You can either have the motor repaired or replaced.
Clogged motor vents can also cause a motor to over heat so make sure the vents and the area around the pump is kept clear of debris.
