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Problem Guides

Heat Pumps

Air source heat pump problems, fault codes, running costs and brand-specific guides

8 free DIY guides · 23 total

Heat pumps are now the UK government's preferred low-carbon heating solution, backed by the Boiler Upgrade Scheme (BUS) grant of up to £7,500 — but they work very differently from a gas boiler, and diagnosing faults requires a different approach. Air source heat pumps need correct flow temperatures, adequate radiator or underfloor heating surface area, and annual maintenance to reach their rated COP (coefficient of performance). These guides cover the most common heat pump problems, brand-specific fault codes for Mitsubishi Ecodan, Daikin Altherma, Vaillant aroTHERM, Worcester Bosch, Samsung EHS, and Grant Aerona3, and how to get the best efficiency from your heat pump installation.

Most popular
1

Heat Pump Error Codes — What They Mean and What to Do

Your heat pump is showing an error code or fault — here's how to respond

2

Vaillant aroTHERM Plus Heat Pump Problems — Faults & Fixes

Vaillant aroTHERM not working, showing fault codes or underperforming

3

Daikin Altherma Heat Pump Problems — Fault Codes & Fixes

Daikin Altherma not working — 7H, A1, E3, EA codes and common faults

All guides
Boiler Upgrade Scheme — how to claim your £7,500 grantFree
Eligibility, application process, and what the BUS grant covers· 30 min
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Daikin Altherma Heat Pump Problems — Fault Codes & Fixes
Daikin Altherma not working — 7H, A1, E3, EA codes and common faults· 30 min–3 hrs
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Grant Aerona3 Heat Pump Problems — Faults & Fixes
Grant Aerona3 not working, poor performance or showing fault codes· 30 min–3 hrs
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Heat Pump Error Codes — What They Mean and What to Do
Your heat pump is showing an error code or fault — here's how to respond· 15 min
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Heat Pump Going Into Defrost — Is It Normal?Free
Heat pump stops briefly and blows cold air or steam — what's happening· 5 min
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Heat Pump Installation Cost UK — 2024 Guide
How much does an air source heat pump cost to install in the UK?· 2–3 days (installation)
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Heat Pump Low COP — Why Efficiency Is Poor & How to Fix It
Heat pump is running but efficiency or COP is much lower than expected· 1–2 hrs
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Heat Pump Making Noise — What's Normal and What's Not
Unusual sounds from the heat pump outdoor or indoor unit· 15 min
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Heat Pump Making Strange Noises
Air source heat pump making loud humming, rattling, clicking, or gurgling sounds· 30 min–3 hrs
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Heat Pump Not Heating the House — Causes & Fixes
House is cold even though the heat pump appears to be running· 30 min–3 hrs
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Heat Pump Not Working in Cold Weather — What to Do
Heat pump struggling or stopping when temperature drops below freezing· 30 min
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Heat Pump Running Costs Too High — How to Reduce ThemFree
Electricity bills higher than expected since the heat pump was installed· 1–2 hrs
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Heat Pump vs Gas Boiler — Which Is Right for Your Home?Free
Considering switching from a gas boiler to a heat pump? Here's what to know· 30 min
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Heat pump grants — the Boiler Upgrade Scheme explainedFree
How to get £7,500 off the cost of a heat pump installation· 30 min read
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Heat pump hot water not hot enough
Why heat pumps produce cooler hot water and how to fix it· 30–60 min
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Heat pump running costs higher than expectedFree
Why your electricity bills have risen and how to optimise heat pump efficiency· Ongoing
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Heat pump vs gas boiler — running costs comparedFree
Which is cheaper to run in the UK right now?· 5 min read
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How does an air source heat pump work?Free
Plain English explanation of how a heat pump heats your home· 5 min read
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How much does an air source heat pump cost in the UK?
Full UK installation costs for air source heat pumps in 2025, including the Boiler Upgrade Scheme grant and what affects the price.· 2–3 days
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Mitsubishi Ecodan Heat Pump Problems — Fault Codes & Fixes
Ecodan not working, showing P1, P5, U7 or other error codes· 30 min–3 hrs
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Samsung EHS Heat Pump Problems — Faults & Fixes
Samsung EHS Gen6 or ClimateHub not working — error codes and common issues· 30 min–3 hrs
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Vaillant aroTHERM Plus Heat Pump Problems — Faults & Fixes
Vaillant aroTHERM not working, showing fault codes or underperforming· 30 min–3 hrs
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Worcester Bosch Heat Pump Problems — Faults & Fixes
Worcester Bosch Compress 7000i or 5000 heat pump not working or showing faults· 30 min–3 hrs
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