When to Call a Heat Pump Engineer – What You Can Check First (and When Not To)

29 Dec

Heat pumps behave differently to boilers, and many apparent “faults” are actually normal operation, control settings, or simple issues. Knowing when to call an engineer — and when you don’t need to — can save time, money, and frustration.

This guide explains what you can safely check yourself, which symptoms usually require professional help, and when delaying a call-out could make things worse.

Before calling an engineer: quick checks worth doing

Many heat pump call-outs are resolved in minutes because a simple check was missed. Before calling an engineer, it’s worth checking the following.

The heat pump and controller both have power
No recent power cut or reset has changed settings
The system is not in holiday, standby, or summer mode
Hot water and heating schedules are enabled
No obvious isolation valves are closed
System pressure is within the normal range

If everything looks correct and the issue persists, it may be time to escalate.

Situations where an engineer is usually needed

Repeated error codes

If the same error code keeps returning after resets, professional diagnosis is needed to identify the underlying cause.

No heating or hot water

Complete loss of heating or hot water that does not respond to settings, boosts, or resets usually requires an engineer.

Flow or circulation faults

Persistent flow errors, noisy pumps, or cold radiators caused by circulation problems often need filter cleaning, balancing, or pump checks.

Electrical or safety-related issues

Tripping breakers, burning smells, visible damage, or water near electrical components should always be handled by a professional.

Issues that often do NOT need an engineer immediately

Frost, steam, or defrost cycles

Frost on the outdoor unit, steam during defrost, and brief pauses in heating are normal winter behaviour.

Lower water temperatures than a boiler

Heat pumps run at lower temperatures by design. Warm radiators can be normal, even when the house is heating correctly.

Heating pauses during hot water reheating

Hot water priority temporarily pauses space heating — this is expected behaviour.

Signs you should call sooner rather than later

Some issues get worse if ignored. You should call an engineer promptly if you notice:

Ice building up and not clearing
Water leaks or repeated loss of system pressure
The heat pump short-cycling repeatedly
The immersion heater running constantly
Performance steadily declining over time

These can indicate underlying flow, drainage, or commissioning issues.

What information to gather before calling

Providing good information helps an engineer diagnose faster. Before calling, note:

Any error codes displayed
When the problem started
Whether heating, hot water, or both are affected
Recent changes (power cuts, servicing, setting changes)
The heat pump make and model

This can reduce diagnosis time and unnecessary repeat visits.

Engineer call-outs and warranties

Many heat pumps are covered by manufacturer warranties that require:

Annual servicing
Work carried out by approved engineers
Faults reported promptly

Attempting complex repairs yourself can risk voiding warranties.

Choosing the right engineer

Heat pumps are not boilers. Always look for an engineer who:

Is experienced with heat pumps specifically
Is familiar with your system type and brand
Understands controls, flow rates, and commissioning

Many problems are settings or system-design related, not component failures.

Key takeaway

Call a heat pump engineer when there are persistent faults, safety concerns, or loss of heating or hot water.

If the issue is minor, intermittent, or clearly linked to normal operation, understanding the system first can save unnecessary call-outs.

Jack Mundinano