Pool pump faults and what they usually mean

Safety first

A pool pump combines water and mains electricity. If the pump trips the earth leakage, smells of burning, sparks, or is sitting in water, switch it off at the isolator and leave it off. Do not open the motor or the electrical box. Electrical work on pool equipment should be done by a qualified person.

The pump hums but does not start

This is one of the most common faults. The usual causes are a failed start capacitor, a seized motor bearing, or an impeller jammed by debris. A humming motor that cannot turn heats up quickly, so switch it off rather than leaving it to try. Capacitors and impeller blockages are routine repairs; a seized motor may need new bearings or a new motor.

The pump runs but little water moves

If the pump has run dry for a while, the seal may already be damaged. Check under the pump for drips.

• Full skimmer or pump basket: empty them.
• Dirty filter: backwash and rinse, and watch the pressure gauge.
• Closed or partly closed valve on the suction or return side.
• Air leak on the suction side: look for bubbles in the pump lid, a cracked lid, a dry O-ring or a loose union.
• Water level below the skimmer opening, so the pump sucks air.
• Blocked impeller, from leaves, seeds or a stray object.

Water leaking under the pump

A steady drip from between the motor and the pump housing is usually the mechanical seal. Seals wear with age, and they fail quickly if the pump runs without water, or if sand gets in. In sandy, windy suburbs along the coast, such as Table View, seals tend to wear faster. A leaking seal is a routine repair, but do not ignore it: water running into the motor end can wreck the bearings.

Leaks at the unions, lid or valves are usually O-rings or gaskets, also routine.

Noises

• Screeching or a rising whine: worn motor bearings.
• Rattling or gravelly sound: debris in the impeller, or cavitation from too little water reaching the pump.
• Clicking that will not start: electrical or capacitor fault.
• Loud hum with vibration: misalignment or failing bearings.

The pump trips the electricity

Tripping can come from water in the motor, a damaged cable, corroded connections or a failing motor winding. In coastal suburbs, salt air corrodes terminals and contacts; in closed, damp pump boxes, condensation can cause the same. Leave the pump off and have it checked by a qualified person.

Pumps can also fail after a power surge when electricity returns after an outage. If yours stopped after an outage, tell the contractor and ask about surge protection.

Filter and valve faults that look like pump faults

Cloudy water despite good chemicals may be old filter sand that no longer filters. Sand appearing in the pool can mean a broken lateral inside a sand filter. Water flowing out of the backwash pipe while filtering means a worn multiport valve gasket. These are all common, repairable faults, and they often get blamed on the pump.

Repair or replace?

Seals, bearings, capacitors, O-rings and valve gaskets are routine and usually worth repairing. A burnt-out motor on an old pump, or a pump whose parts are no longer available, may be better replaced. If you replace, choose a pump sized for your pool and filter: bigger is not better. A variable-speed pump can lower running costs, though it costs more to buy; ask the contractor to compare. We do not publish prices. See pool pump and equipment repair, or the local pages for Durbanville, Bellville and Brackenfell.

Frequently asked questions

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