Typical repairs fall within a guide range of £90–£1,100, including VAT, depending on the part and the time involved. Refrigerant repairs must be done by an F-gas certified engineer. Regular heat pump servicing catches many of these faults before they stop the system working.
Heat pump owners in Hertfordshire can arrange a fault-finding visit at a rate agreed before an engineer attends. Repairs in Hertfordshire that need a part ordered are explained and priced before the engineer leaves. For repeated faults in Hertfordshire, the engineer looks at the system design as well as the failed part.
Who it suits
- Systems losing pressure or needing frequent topping up
- Outdoor units that have become noisy, iced up or keep switching on and off
- Rooms or hot water not getting warm enough
- Heat pumps installed by another company that need a second opinion
Grants and rules for heat pumps in England
Homes in Hertfordshire can use the Boiler Upgrade Scheme, which takes £7,500 off the cost of an air source heat pump when it replaces fossil-fuel or electric heating. Replacing oil or LPG heating qualifies for £9,000 for installations from 21 July 2026 to 31 March 2027, and air-to-air systems for £2,500. The MCS-certified installer named in your quote applies for the grant and deducts it from the price.
Heat pump repairs prices in Hertfordshire
Guide prices for Hertfordshire, including VAT. We agree the visit rate before anyone attends, so there are no surprises on the day.
| Repair | Guide price |
|---|---|
| Fault-finding visit and diagnosis | £90–£190 |
| Sensor or thermistor replacement | £130–£290 |
| Expansion vessel or pressure relief valve | £160–£370 |
| Circulating pump replacement | £260–£500 |
| Fan motor replacement | £320–£680 |
| Refrigerant leak repair and re-gas (split systems) | £370–£1,000 |
| Main control board (PCB) replacement | £470–£1,150 |
Inc VAT. The fault-finding rate is agreed before we attend; repairs are priced in writing before parts are ordered.
Towns we cover in Hertfordshire
We cover 17 towns in Hertfordshire for heat pump repairs. Each links to local guide prices and the grant position for England.
| Town | Postcode district | Nearest town | Midwinter daylight |
|---|---|---|---|
| Hemel Hempstead | HP2 | Berkhamsted | 7 h 47 min |
| Stevenage | SG1 | Hitchin | 7 h 45 min |
| St Albans | AL1 | Radlett | 7 h 47 min |
| Welwyn Garden City | AL8 | Hatfield | 7 h 46 min |
| Cheshunt | EN8 | Hoddesdon | 7 h 47 min |
| Hatfield | AL10 | Welwyn Garden City | 7 h 47 min |
| Bishop's Stortford | CM23 | Ware | 7 h 46 min |
| Hitchin | SG6 | Letchworth Garden City | 7 h 45 min |
| Hoddesdon | EN11 | Ware | 7 h 47 min |
| Letchworth Garden City | SG6 | Hitchin | 7 h 45 min |
| Harpenden | AL5 | St Albans | 7 h 46 min |
| Hertford | SG13 | Ware | 7 h 47 min |
| Berkhamsted | HP4 | Tring | 7 h 47 min |
| Ware | SG12 | Hertford | 7 h 46 min |
| Royston | SG7 | Letchworth Garden City | 7 h 44 min |
| Radlett | WD7 | St Albans | 7 h 48 min |
| Tring | HP23 | Berkhamsted | 7 h 47 min |
Heat pump repairs questions
Why is my heat pump showing an error code?
An error code is the heat pump's way of reporting a problem it has detected, such as low water flow, a sensor reading out of range or a communication fault between units. Note the code and check the manual, as some codes clear after a simple reset or pressure top-up. If it returns, an engineer can trace the underlying cause.
Why does my heat pump keep switching on and off?
Frequent starting and stopping, called short cycling, is usually caused by an oversized heat pump, low water flow, too many zones closing at once or controls set with too narrow a range. It reduces efficiency and wears components. An engineer can check the settings, flow rates and design, and can often improve it with control changes before any parts are needed.
Is ice on my heat pump a fault?
Some frost on the outdoor unit in cold, damp weather is normal, and the unit clears it with regular defrost cycles, often releasing a little vapour. It becomes a fault when thick ice builds up and does not clear, or when ice blocks the fan. That can point to poor airflow, a failed sensor, drainage problems or low refrigerant, and needs checking.
Do refrigerant repairs need a specialist?
Yes. Any work on a heat pump's refrigerant circuit, such as tracing a leak, replacing a component or re-gassing, must by law be done by an F-gas certified engineer where the refrigerant is fluorinated, such as R32; units using R290 (propane) need an engineer trained in flammable refrigerants. On split systems the refrigerant runs through pipes inside your home, so leaks there are more likely than on sealed monobloc units.