Heat pumps · Priority

Heat Pump Low Pressure Fault

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

This fault is normally treated as priority work because the plant is still running but is damaging itself or wasting energy while it does.

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: Priority
Call: 069 268 0988

What we find

Likely causes

Refrigerant leak
Blocked or iced evaporator
Failed defrost sensor or cycle
Restricted expansion valve or filter drier
Fan not running at correct speed

Test sequence

How we diagnose it

Nitrogen pressure and vacuum hold test
Electronic leak trace at joints and coil
Defrost cycle observation
Superheat measurement across the expansion device

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 Not Heating Water

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

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.

FAQs

Frequently asked questions

What causes heat pump low pressure fault?

The usual causes are refrigerant leak, blocked or iced evaporator, failed defrost sensor or cycle, restricted expansion valve or filter drier. Which one it is can only be confirmed by measurement, not by symptom alone.

How do you diagnose it?

Nitrogen pressure and vacuum hold test; Electronic leak trace at joints and coil; Defrost cycle observation; Superheat measurement across the expansion device. The readings are recorded so the repair decision is based on data.

Can I keep using the system in the meantime?

Usually yes, for a short period, but efficiency and component life are both being lost while the fault persists.

Where do you attend this fault?

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

Get heat pump low pressure fault diagnosed

Priority attendance across Johannesburg, Ekurhuleni, West Rand, Midrand, Centurion and Pretoria.

069 268 0988 Request a quote