Heat Pump Repair in Bristol
A heat pump that has stopped heating, is making a new noise or is pushing up your bills usually has a fixable cause. Here's what to check yourself, the faults that come up in Bristol homes, and what repairs typically cost.
Last reviewed: 2 October 2026
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Check the breaker first
a tripped circuit or an error code on the controller explains a surprising share of 'dead' heat pumps — both are quick to check before anyone visits.
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Refrigerant work needs F-Gas
only an engineer holding F-Gas certification can legally open the sealed refrigerant circuit, so ask before booking anyone for a refrigerant fault.
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Most faults are fixable
sensors, valves, fans and controller boards fail far more often than compressors, and most are replaced rather than the whole unit.
Five checks before you call anyone
These take a few minutes, need no tools, and sometimes solve the problem outright. Even when they don't, the answers help an engineer arrive with the right parts.
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Is there power?
Look at your consumer unit. Heat pumps usually have their own breaker, sometimes labelled 'ASHP' or 'heat pump'. If it has tripped, reset it once. If it trips again, leave it off and get help.
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What does the controller say?
Write down any error code shown on the controller or app. It tells the engineer where to start and which parts might be needed.
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Has a setting changed?
Holiday mode, a schedule edited by mistake, or a lowered heating curve can all look like a fault. Compare the settings with your handover notes.
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Is the outdoor unit blocked?
On Bristol's tree-lined streets — Redland, Westbury-on-Trym, Sneyd Park — leaves pile up against outdoor units in autumn. Clear anything blocking the grille, with the power off.
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Is the system pressure normal?
Many systems have a pressure gauge near the cylinder. If it reads well below the level marked at installation, the system may need topping up or have a small leak.
Faults that come up in Bristol homes
Two local conditions shape which faults appear most: Bristol's hard, limestone-fed water, which scales up cylinder coils, and its mild but damp winters, which make defrost cycles a routine part of a heat pump's day.
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Weak hot water or slow reheating
Bristol Water's supply is moderately hard to very hard because it runs off limestone. Over several years, scale builds on the cylinder's heating coil and slows reheating. Descaling the coil, or fitting a scale reducer, usually fixes it.
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Ice that won't clear
Damp Bristol winters mean defrost cycles are routine. Ice that builds up and doesn't clear points to a faulty defrost sensor, a fan that isn't turning, or low refrigerant.
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Rooms colder than they used to be
Often a changed heating curve, air in the radiators, a sticking valve, or a dirty magnetic filter. Less often, a refrigerant problem.
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Error code but still heating
Many codes flag minor conditions such as a sensor reading out of range or a communication hiccup. The engineer reads the log and decides whether it needs a part.
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New or louder noise
Rattling or humming from the outdoor unit usually means a worn fan bearing, loose panel or debris in the fan. Get it checked before it damages anything else.
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Bills up with no change in use
A drop in efficiency usually has a cause: a blocked coil, low refrigerant, a drifted sensor or a setting change. The engineer compares current performance with the commissioning record.
What repairs typically cost
Expect a diagnostic visit to cost around £80–£150 in the Bristol area. After that, cost depends on the part:
- Sensors, valves, filters and seals: roughly £15–£200 plus labour
- Fan motors, expansion valves and controller boards: roughly £200–£600 plus labour
- Compressor replacement: £800–£2,500 or more plus labour
If the system is still under manufacturer warranty, parts may be covered, provided the annual service record is up to date. Ask for a written quote before agreeing to any parts-based repair, and for a replacement estimate alongside it if the system is old and the repair is major.
Getting an engineer out
Use the form on our homepage to describe the problem. A local heat pump engineer from our network will be in touch to arrange a diagnostic visit. To help them, include:
- the make and model of the heat pump, from the outdoor unit's label or your MCS certificate
- any error code on the controller
- when the problem started and whether you have any heating or hot water now
- whether the system is still under warranty
Common brands in Bristol homes include:
- Vaillant aroTHERM plus
- Mitsubishi Electric Ecodan
- Daikin Altherma
- Samsung EHS
- Grant Aerona
- Worcester Bosch
Repair questions
My heat pump has stopped completely. What should I do first?
Check the heat pump's breaker in the consumer unit and reset it once if it has tripped. Then look for an error code on the controller and note it down. If the breaker trips again, or there's a code you can't clear, leave the system off and arrange a diagnostic visit. Your immersion heater, if the cylinder has one, can keep hot water going in the meantime.
What does a heat pump repair cost in Bristol?
A diagnostic visit usually costs around £80–£150. Small parts such as sensors and valves are typically £15–£200 plus labour; fan motors and controller boards £200–£600; and a compressor £800–£2,500 or more. Any engineer should give you a written quote before carrying out work that needs parts.
Is my repair covered by the manufacturer's warranty?
Possibly. Manufacturer warranties on heat pumps commonly run five to ten years or more, but most require an annual service record. Find your MCS certificate and warranty paperwork before the engineer visits — they'll need the model and serial number to check.
Why does my hot water take longer to heat than it used to?
In Bristol, the most likely cause is scale on the cylinder's heating coil from the area's hard water. Other causes include a faulty cylinder sensor or a change to the hot water schedule. Descaling and a scale reducer usually solve it.
Can any heating engineer fix a heat pump?
Not every heating engineer works on heat pumps. Electrical and water-side faults can be handled by a heat pump-trained engineer, but anything involving the refrigerant circuit needs F-Gas certification. Ask whether the engineer is familiar with your brand.
Is it worth repairing an older heat pump?
Usually. Heat pumps typically last 15–20 years and most faults are in replaceable parts. The repair-or-replace question tends to arise only when the compressor fails on an older system outside warranty. Ask for a repair quote and a replacement estimate side by side.
Will a repair affect my Boiler Upgrade Scheme grant?
No. The grant was paid when the system was installed and isn't affected by later repairs.
Ask about a heat pump repair
Tell us what's happening, including any error code and the make of your heat pump. A local heat pump engineer from our network will be in touch.