Heat pumps · Same-day

Heat Pump Not Heating Water

The unit runs but water stays cold or only reaches lukewarm temperatures.

This fault is normally treated as same-day work because the site has effectively lost hot water, steam or safe operation.

Gauteng municipal water is moderately hard, so scale on elements and heat exchangers is the single most common cause of falling performance.

069 268 0988 info@reyds.co.za

Equipment: Heat pumps
Priority: Same-day
Call: 069 268 0988

What we find

Likely causes

Low refrigerant charge from a slow leak
Failed compressor or start capacitor
Fouled evaporator restricting airflow
Faulty water temperature sensor holding the unit off
Reversing valve stuck in the wrong position

Test sequence

How we diagnose it

Measure suction and discharge pressures against ambient
Check compressor current draw versus nameplate
Verify sensor resistance against the manufacturer curve
Measure water delta-T across the condenser

Repair route

Services that resolve this fault

Heat Pump Repairs

Fault-finding and repair of air-source hot water and pool heat pumps.

Industrial Heat Pump Repairs

High-capacity and cascade heat pump repairs for plants and process water.

Commercial Heat Pump Repairs

Hotel, guesthouse, gym and complex heat pump repairs with minimal downtime.

Heat Pump Maintenance

Scheduled servicing that keeps COP high and prevents compressor failure.

Heat Pump Installation

Sizing, plumbing, electrical and commissioning for new heat pump plant.

Heat Pump Regassing

Leak detection first, then correct-charge regassing by weight.

Heat Pump Troubleshooting

Structured diagnostics for intermittent and error-code faults.

Commercial Heat Pump Regassing

Leak repair and charge correction on multi-unit commercial plant.

Coverage

Attendance by area

Also check

Related faults

Heat Pump Keeps Tripping the Breaker

The circuit breaker or earth leakage trips shortly after the heat pump starts.

Heat Pump Leaking Water

Water pooling under or around the unit, sometimes continuously.

Heat Pump Making Noise

Rattling, grinding, screeching or loud humming during operation.

Heat Pump Compressor Fault

The compressor will not start, hums and trips, or cuts out on overload.

Heat Pump High Pressure Fault

The unit locks out on a high pressure error, often after running for a while.

Heat Pump Low Pressure Fault

The unit trips on low pressure, typically in cold weather or early morning.

FAQs

Frequently asked questions

What causes heat pump not heating water?

The usual causes are low refrigerant charge from a slow leak, failed compressor or start capacitor, fouled evaporator restricting airflow, faulty water temperature sensor holding the unit off. Which one it is can only be confirmed by measurement, not by symptom alone.

How do you diagnose it?

Measure suction and discharge pressures against ambient; Check compressor current draw versus nameplate; Verify sensor resistance against the manufacturer curve; Measure water delta-T across the condenser. The readings are recorded so the repair decision is based on data.

Can I keep using the system in the meantime?

No — isolate the plant and call 069 268 0988. Running it in this condition risks further damage or an unsafe situation.

Where do you attend this fault?

Across Johannesburg, Ekurhuleni, West Rand, Midrand, Centurion and Pretoria.

Get heat pump not heating water diagnosed

Same-day attendance across Johannesburg, Ekurhuleni, West Rand, Midrand, Centurion and Pretoria.

069 268 0988 Request a quote