How Pumps Work & Troubleshooting

Most pumps are self-priming centrifugal pumps. These pumps must have a vacuum chamber, commonly known as a pump housing. The pump housing must be filled with water in order for any pump to create a vacuum, resulting in your pump pulling the water out of your pool or spa. The pump housing will remain full of water while the pump is on, and will remain full or partially full of water when the pump is shut off.

When you turn on the pump the motor will begin to rotate on high speed. The motor drives the pump impeller, located inside the pumps centre portion at the opposite end, away from the electrical switch portion of the motor. While the motor is rotating, the tips of the impeller are sealed hydraulically inside of the pump diffuser, this allows self-priming to occur.

Self-priming can only occur when the pump has a diffuser. Some pumps have a separate diffuser, others have the diffuser moulded into the pump's cover, refer to your Owner's Manual for your pump. The diffuser helps to eliminate any air coming into the pump housing, suction piping, or hoses on above ground pools. When all the air is being removed from the system, you will notice the bubbles returning to the pool through the return fittings. The impeller acts to convert water velocity into water pressure, which is registered on your filter pressure gauge. The actual Litres Per Minute (LPM) varies with the type of pump and the horsepower. Check your Owner's Manual for more information (owner's manuals can be found online under the detailed page of your pump).

Self-priming pumps are very dependable and simple in design. They require a sufficient supply of water from the pool or spa, and no air in the suction lines. Air could come from a loose strainer cover, a leak in any valve, a pin hole in any suction line or any crack or loose connections in the underground piping. Your pump should be kept free of dirt and also located where it can be protected from flooding during heavy rain fall. If your pump motor becomes flooded you will probably have to replace it (pump motors damaged by flooding are not covered by warranty).

My pump doesn't Run

Check the power, breakers, switches, etc. If you have a timer on the system, make sure it is working properly. If the pump is tripping the main breaker circuit to the house, there is a good chance the motor on the pump is water logged from possible flooding or insufficient covering.

My pump is running too hot and cutting off?

This may be caused by insufficient power due to an undersized or long power wires. All wires should be according to code requirements and the motor manufacturer's recommendations. Your pump has a thermal overload, which will shut the motor off when it gets too hot, and it will restart itself once it has cooled down.

My pump is noisy

This may be normal since they produce water flow. The motor has a cooling fan internally which can be heard to a certain degree. It is advisable not to locate any pool pump under someone's bedroom window. The pump's sounds can be caused by vibrations between the pump base and the base or concrete pad it is sitting on. A piece of old carpet or rubber between the pump and base may quiet the sound.

The bearings may be noisy due to normal wear or from dry running the pump. Feeding high concentrations of chemical tablets in the skimmer will cause corrosive damage to the pump seal, which can leak and damage the motor bearings. It is recommended to get the bearings replaced by a qualified motor repair shop. Also, cavitations due to improper suction line sizing, leaks in the piping, a blockage in the suction line, or a low level of pool water will cause higher than normal sound.

Why are bubbles coming into the pool?

• The strainer cover is loose or the gasket is damaged; check and replace the cover or gasket if necessary.
• The pool water level may be too low allowing air to mix with water through the skimmer, you will need to raise the water level.
• The skimmer weir, sometimes called the flapper, may be stuck in the up position, allowing air to mix with water in the suction line.
• There can be a leak at any connection in the suction piping or a leak inside any suction side valve at the stem o-ring.
• Also, there may be a leak in the underground piping, caused by a loose joint, or termites/ants that will chew into some flexible piping.

My pump is running, but there is no pressure. Why?

Many pool owners use this term when in fact they really mean they have lots of pressure but their flow is very low. This is caused by a dirty or clogged filter, a blocked return line, or a valve that is shut off or partially shut on the return piping.

The pump's impeller may be clogged with debris. Check by first shutting off the pump. Remove the basket and check the impeller by putting your finger into the suction hole found in the pump strainer housing. If the seal is broken, replace it.

My Pump in leaking between motor and pump housing

When the pump leaks between motor and pump housing it is because the mechanical seal is damaged.

Causes:

Wear and tear

Dry running a pump for long periods of time will cause the mechanical seal to burn out. When there is no water in the pump housing the mechanical seal has no lubricant!. To avoid this problem make sure your pool water levels remain above the weir height. If your pump does not stay primed it’s advisable to install a check valve/ non-return valve on the suction line. Mechanical Seals damaged by dry running are not covered by warranty.

My pump will not prime. Why?

Check for each of the following:

• You may have a suction leak if there is not enough water in the strainer housing.
• You can have a leak at any joint especially at the first fitting that is screwed into the strainer housing.
• The strainer cover may be loose or an o-ring under the strainer housing cover may be worn.
• You may have clogged suction piping, which is caused by items that get sucked through the skimmer into the piping, usually lodging at any turn in the piping.
• Sometimes when the pump starts, a small stone or debris by-passes the pump basket it will break the impeller.
• The pump may be located above the pool water level or may be too far from the pool, requiring longer periods to prime. The ideal situation is to locate the pump at or just slightly above water level, 2 meters maximum, and as close to the pool as possible, approximately 3 - 6 meters maximum.
• It might be necessary to install a check valve/ non-return valve on the suction line. This will help to keep the pump primed at all times.