This page covers heat pumps specifically. For solar and gas heating, and for choosing between heating types, see pool heater repairs.
The most useful thing to know about heat pump faults: a large share of them are not heat pump faults at all. They are flow problems, and the check costs almost nothing.
Tell us what the unit is doing and how old it is.
Get Heat Pump Repair QuotesCheck Flow First
The most common heat pump complaint in Pretoria is a unit that runs without heating the pool, and the most common cause is not the heat pump.
- 1('Check the filter', 'A dirty filter restricts flow. Backwash or clean it and see whether performance recovers before anything else is considered.')
- 2('Check the pump and baskets', 'A failing pump, or blocked skimmer and pump baskets, starve the heat pump of water.')
- 3('Check the valves', 'A partly closed valve, or a bypass left open, sends water around the unit rather than through it.')
- 4('Check run time', 'A heat pump only heats while the pump circulates. If the timer has drifted after power interruptions, actual heating hours may be far below what you think.')
- 5('Then call someone', 'If flow is confirmed good and it still will not heat, the fault is likely in the unit and worth diagnosing properly.')
A meaningful share of heat pump call-outs end with a filter clean and a valve adjustment. Working through the list above first costs nothing and frequently resolves it.
Common Heat Pump Faults
| Symptom | Likely cause | Indicative repair |
|---|---|---|
| Runs, does not heat | Inadequate water flow — filter, pump, valves | Often free to resolve; otherwise R600 – R1,500 diagnosis |
| Will not start at all | Power supply, capacitor, contactor or controller | R900 – R3,500 |
| Trips the breaker | Electrical fault or a failing compressor | R1,200 – R9,000 |
| Heavy persistent icing | Low refrigerant, defrost sensor, restricted airflow | R1,500 – R6,000 |
| Noisy fan or vibration | Fan motor or bearing wear | R1,200 – R4,000 |
| Error code displayed | Sensor or control fault, or a protective lockout | R900 – R3,500 |
| Heats poorly, always has | Undersized for the pool volume, or no cover | Sizing question rather than a fault |
| Compressor failed | End of life, particularly on older units | R6,000 – R15,000, often uneconomic |
These are indicative market ranges, not a quotation. They are compiled from published South African pool industry pricing to give you a starting point for budgeting. They are not the rate card of any company on this platform, and no figure here is a commitment by anyone.
Repair or Replace
| Failed component | Usual answer |
|---|---|
| Sensor, capacitor, contactor, controller | Repair. Modest cost, straightforward. |
| Fan motor | Repair, usually worthwhile. |
| Refrigerant leak, locatable | Repair, if the leak can be found and properly fixed. |
| Evaporator coil, corroded (coastal) | Depends on cost against unit age. Coastal corrosion often takes the coil first. |
| Compressor, unit under ~7 years | Usually repair, particularly if any warranty remains. |
| Compressor, unit over ~10 years | Usually replace. Repair cost approaches a new unit with better efficiency and a fresh warranty. |
Replacement runs roughly R18,000 to R55,000 supplied and installed, sized to pool volume. Oversizing wastes money; undersizing means a unit that never quite gets there. Sizing should follow the actual pool volume and how you intend to use it, not a rule of thumb.
Winter Operation and Defrost
Pretoria winters are dry and cold enough at night for defrost behaviour to matter. A heat pump pulls heat out of the air, so its output drops as the air gets colder, and on a frosty morning the evaporator coil ices up and the unit spends part of its cycle clearing that ice rather than heating the pool. A unit that seems to have lost power in June is often working exactly as designed.
Two things genuinely go wrong here. Defrost that never terminates points at a sensor or the reversing valve. And an outdoor unit that has been running all summer on dusty Highveld air will have a coil packed with dust and grass seed, which looks like a refrigerant fault and is really a cleaning job. Siting the unit out of the dust line and rinsing the coil periodically helps materially.
Related Services
Heat pumps are one of the equipment services covered by Swimming Pool Repairs Pretoria.
Swimming Pool Heat Pump Repairs FAQs
My heat pump runs but the pool does not warm up. Why?
Check flow before anything else. A heat pump needs adequate water through it to transfer heat, and a dirty filter, a failing pump, a blocked basket or a partly closed valve all starve it. The unit runs, uses electricity, and heats almost nothing.
This is the single most common heat pump complaint and it is frequently free to fix. Clean the filter, check the pump and confirm the valves before booking a repair.
How cold is too cold for a pool heat pump?
Heat pumps extract heat from the air, so output falls as air temperature drops. Most units work well down to around 10°C and become progressively less efficient below that.
In Pretoria that means good performance through most of the swimming season and reduced output on cold winter mornings. A unit that has always struggled in mid-winter may be correctly sized and simply reaching its limit.
Is my heat pump worth repairing or should I replace it?
Broadly, a fault in controls, fan, sensors or a valve is worth repairing. A failed compressor on an older unit usually is not, because compressor replacement can approach the cost of a new heat pump with a fresh warranty and better efficiency.
Part availability matters too. On a unit more than about ten years old, the manufacturer may no longer support it, which decides the question regardless of condition.
The unit is icing up. Is that normal?
Some frosting on the evaporator in cold conditions is normal and units have a defrost cycle for it. Persistent heavy icing is not, and usually points at low refrigerant, a faulty defrost sensor, or restricted airflow.
Restricted airflow is worth checking yourself — heat pumps need clear space around them, and a unit boxed in by planting or screening cannot breathe.
Does a pool cover make much difference with a heat pump?
A very large difference. Most heat loss from a pool is evaporation from the surface, and a cover addresses it directly. A heated pool without a cover in Pretoria wind is heating the air.
Of everything you can do to reduce heating costs, a cover is the highest return by a wide margin, and it usually pays for itself well within a season.
What does a heat pump repair cost?
Commonly R2,500 to R9,000 depending on the fault. Sensors, capacitors, fan motors and controls sit at the lower end; refrigerant work and compressors at the upper end and beyond.
Diagnosis is usually R600 to R1,500 and often credited against the repair. On an older unit, ask what a replacement would cost before committing to a major repair.
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