Heat pump repair in Scotland
Heat pumps are reliable, but when one does go wrong the symptoms are unfamiliar to most households and the causes are rarely what people expect. We repair air source heat pumps across East Lothian and Midlothian, including Mitsubishi Ecodan and the other major systems.
Gas Safe
OFTECAir source heat pump repairs
If your heat pump has stopped heating, frozen or is making noise, our engineers diagnose and repair air source heat pumps across Scotland. We are a heat pump engineer covering Edinburgh and East Lothian, working on Ecodan and all major brands.
Not reaching temperature
Frequently a controls or flow temperature issue rather than a failed unit. We check the whole system before condemning the heat pump.
Noise and vibration
A heat pump should be quiet. New rattles, hums or vibration usually point to the fan, the mountings or a refrigerant issue worth catching early.
Icing and defrost faults
Some frost on the outdoor unit in a Scottish winter is normal. Persistent heavy icing is not, and it points to a defrost cycle that is not working properly.
How it works
Call us
Tell us what the system is doing and read out any code on the controller. That usually shortens the diagnosis considerably.
Whole-system diagnosis
We check the controls and the flow temperatures as well as the unit, because the fault is often not where the symptom appears.
Agree the work
You get a clear explanation of what is actually wrong before anything is replaced or charged for.
Repair and verify
We complete the work, then run the system and confirm it is performing as it should before leaving.
What happens on a heat pump repair visit
Heat pump faults are diagnosed across the whole system, because the outdoor unit is often reporting a problem that starts elsewhere.
- Fault codes read from the controller and interpreted against the manufacturer documentation
- Flow and return temperatures measured, to see what the system is actually doing rather than what it should be
- Refrigerant circuit checked for pressure and signs of loss
- The defrost cycle observed and confirmed to be operating correctly
- Controls, weather compensation and schedules reviewed, since poor setup mimics a great many faults
- The cylinder, its coil and the immersion checked where hot water is the complaint
- A written explanation of what was wrong, what was done and what to watch for
If the system turns out to be correctly working but poorly configured, we will say so and set it up properly rather than sell you a part.
Most heat pump complaints are setup, not failure
The commonest call we get about heat pumps is that the house does not feel warm enough, and in the majority of those cases the equipment is working exactly as designed. What has gone wrong is the configuration, usually a flow temperature set too low for the radiators actually installed, or a heating schedule copied over from how a gas boiler used to run.
Heat pumps do not behave like boilers. They work best running steadily at a lower flow temperature for long periods, rather than being fired hard in short bursts morning and evening. A schedule that made sense for a combi will make a heat pump look weak and expensive.
That is worth knowing before you pay for a repair. A proper diagnostic visit should always start with the settings and the system, and only then move on to the hardware.
Heat pump repair questions, answered
Why is my heat pump not heating the house properly?+
Most often the flow temperature or the heating schedule is set for how a gas boiler used to run rather than for a heat pump. It is worth checking the configuration before assuming the unit has failed.
Is it normal for the outdoor unit to ice up?+
A degree of frost in cold weather is entirely normal and the defrost cycle clears it. Persistent heavy icing is not normal and suggests the defrost cycle is not working correctly.
My heat pump has become noisy. Is that serious?+
It is worth looking at promptly. New rattles or vibration usually point to the fan or the mountings, and a change in tone can indicate a refrigerant issue that is better caught early.
Do you repair Mitsubishi Ecodan systems?+
Yes. We work on Ecodan and the other major air source systems, including units we did not install ourselves.
Should a heat pump run all the time?+
Broadly yes. Heat pumps are most efficient running steadily at a lower flow temperature for long periods, which is the opposite of how most people ran their old boiler.
Will a repair affect my warranty?+
Warranty terms vary by manufacturer, so tell us the make and age when you call and we will advise on the right route before doing anything that might affect cover.
Can you look at a system another company installed?+
Yes. A good deal of our heat pump work is on systems installed by others, often where the original setup was never properly commissioned.
What local customers say
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Page last updated: 27 August 2026