You can handle the basic housekeeping yourself (keeping the outdoor unit clear, checking the condensate drain, watching the app for warnings and bleeding radiators) but anything involving the refrigerant circuit, electrical connections or internal components legally requires a qualified, F-Gas certified engineer. Get this split right and you’ll protect both your warranty and your running costs.
Most of the calls we get about heat pump “faults” turn out to be one of two things: either a homeowner task that’s been left too long, or a homeowner attempting something that needed a qualified visit. Knowing exactly where that line sits saves you money, keeps your system efficient, and stops you accidentally invalidating cover you’re paying for. Here’s exactly who does what.
Why does the split between homeowner and engineer tasks exist?
The split exists for three reasons (safety, legal requirement, and warranty protection), and it isn’t arbitrary. It’s worth understanding all three because they explain why “I’m quite handy” doesn’t change the answer.
- Safety. Heat pumps run on mains electricity and contain a sealed refrigerant circuit under pressure. Opening either without training risks electric shock or exposure to refrigerant gas, which can cause frostbite on contact and is harmful if inhaled in a confined space.
- Legal requirement. Under F-Gas regulations, anyone who breaks into a refrigerant circuit (to check charge, top up, or repair a leak) must hold F-Gas certification. This isn’t a manufacturer preference, it’s UK law, and it applies regardless of how confident you feel with a set of gauges.
- Warranty protection. Every heat pump manufacturer’s warranty is conditional on annual servicing by a suitably qualified engineer, and most explicitly exclude damage caused by unauthorised interference with sealed components. Have a go yourself and you risk voiding cover on a unit that cost several thousand pounds to install.
With that context, the split below isn’t us being overly cautious. It reflects what’s actually safe, legal and sensible for a homeowner to do, and what needs a visit.
What heat pump maintenance can you safely do yourself?
You can safely handle five things yourself: keeping the outdoor unit clear, monitoring the system, keeping the indoor unit area clear, checking radiators, and checking filters where accessible. None of it requires any qualification, and doing them regularly is one of the biggest factors in keeping your system running efficiently between annual services.
How do you keep the outdoor unit clear?
Check it roughly monthly through autumn and winter, and more often during snow or after storms, since the outdoor unit needs unobstructed airflow to work properly. It’s drawing in outside air to extract heat from it, even in winter, so blocking that airflow directly hits efficiency:
- Clear leaves, garden debris and grass cuttings away from the base and sides
- Brush snow off the top and sides gently. Don’t chip at ice with anything sharp
- Keep at least the manufacturer’s recommended clearance free on all sides (check your installation manual, as this varies by model)
- Make sure nothing’s been stacked against it. Bins, bikes, stored timber and planters are common culprits
- Check that the condensate drain outlet at the base isn’t blocked or frozen over, since a blocked drain can cause water to back up and ice around the unit
How do you monitor the system without digging into it?
Monitor it through the pressure gauge, app warnings and running costs. Modern heat pumps give you a lot of visibility without needing to touch anything internal:
- Check the pressure gauge if your system has one visible on the indoor unit or cylinder cupboard. You’re looking for it sitting within the normal range stated in your user manual, typically around 1–2 bar for a sealed heating system, not for any ability to adjust it yourself
- Check the app or in-room display regularly for warning codes or error messages, and note them down even if the system seems to be running fine. A code you catch early is far easier to diagnose than one you report weeks later
- Keep an eye on unusually high running costs or a system that seems to be working harder than usual to reach temperature, both of which are useful information for an engineer even if you can’t fix the underlying cause yourself
How do you keep the indoor unit area clear and ventilated?
Keep the space free of clutter, ventilated and dry. Whether your heat pump’s indoor components sit in an airing cupboard, utility room or plant room, that space needs to breathe and stay accessible:
- Don’t stack boxes, laundry or storage against the unit
- Make sure any ventilation grilles into the cupboard aren’t blocked
- Keep the area dry. Damp cupboards are bad for electrical components generally
- Leave clear access for an engineer to reach isolation switches and service points without moving furniture first
How do you check your radiators and general heating health?
Feel each radiator while the heating is running and bleed any with a cold top and warm bottom. It’s a job any homeowner can do, and it matters more with heat pumps because they run at lower flow temperatures than old gas boilers, which makes trapped air in radiators more noticeable as cold spots:
- Feel each radiator when the heating is running. A cold patch at the top usually means trapped air, cold at the bottom often means sludge or debris
- Bleed radiators with a cold top and warm bottom using a standard radiator key, and top up system pressure afterwards if it drops below the normal range
- If radiators are cold at the bottom even after bleeding, that’s a job for an engineer. It usually points to a power flush being needed, which isn’t a DIY task
How do you check filters, where accessible?
Check your installation manual first, since this varies by system rather than being something to assume. Some heat pumps have a user-accessible filter on the indoor unit or at the cylinder that you can slide out, rinse and refit every few months. Others have filters that are only accessible by removing panels or that the manufacturer specifies as an engineer-only task during the annual service. Don’t force a panel open to get at a filter if your manual doesn’t describe it as user-serviceable.
What heat pump maintenance needs a qualified engineer?
Six tasks need a qualified engineer (refrigerant circuit checks, electrical inspections, heat exchanger cleaning, sensor calibration, COP verification and compressor checks) because they all involve either the refrigerant circuit, electrical systems, or internal components that require diagnostic training and calibrated equipment to check properly.
Why do refrigerant circuit checks and top-ups need a qualified engineer?
By law, only an F-Gas certified engineer can break into the sealed refrigerant circuit to check charge levels, test for leaks, or top up refrigerant. This is the single most common misunderstanding we come across: homeowners assuming a heat pump works like topping up a car’s air conditioning. It doesn’t, and attempting it yourself is both illegal and hazardous.
Why do electrical connection inspections need a qualified engineer?
An engineer inspects electrical connections because heat pumps draw significant current, particularly on startup, and loose or corroded connections are a common cause of intermittent faults and, in rare cases, fire risk. They check terminal tightness, cable condition and earthing as a standard part of the annual service. This needs the unit isolated correctly first, which itself requires knowing the system.
Why does heat exchanger cleaning and inspection need a qualified engineer?
Proper cleaning and inspection requires the unit to be partially disassembled, which isn’t something to attempt without training. The heat exchanger is where the actual heat transfer happens between refrigerant and your heating water, and it can pick up scale or debris over time that reduces efficiency.
Why does sensor and control calibration need a qualified engineer?
An engineer checks your heat pump’s temperature sensors and control system against known reference points and recalibrates where drift has occurred, using diagnostic equipment most homeowners simply don’t have. These sensors were originally calibrated to your specific setup during commissioning.
Why does full system performance and COP verification need a qualified engineer?
Verifying performance properly means an engineer comparing live readings against commissioning data, which isn’t visible from the app alone. Coefficient of Performance (COP), the ratio of heat output to electricity input, is the key measure of whether your system is running as efficiently as it should against its original design specification.
Why do compressor and internal component checks need a qualified engineer?
Engineers check the compressor for unusual noise, vibration, and electrical draw patterns that can flag early wear long before it becomes a breakdown. This is diagnostic work, not a visual check. It matters because the compressor is the most expensive single component in a heat pump and the one most sensitive to running conditions.
Which maintenance tasks fall to the homeowner and which need an engineer?
| Task | Who does it | Frequency | Why it matters |
|---|---|---|---|
| Clearing outdoor unit of leaves/snow/debris | Homeowner | Monthly (autumn/winter) | Maintains airflow, protects efficiency |
| Checking condensate drain isn’t blocked/frozen | Homeowner | Monthly (winter) | Prevents icing and water backup |
| Monitoring pressure gauge and app warnings | Homeowner | Monthly, or on any alert | Catches issues early, informs engineer visits |
| Keeping indoor unit area clear/ventilated | Homeowner | Ongoing | Protects electrical components, keeps access clear |
| Bleeding radiators / checking for cold spots | Homeowner | As needed, check each autumn | Ensures even heat distribution |
| Cleaning user-accessible filters (model dependent) | Homeowner | Every 1–3 months if applicable | Maintains airflow and efficiency |
| Refrigerant circuit checks and top-ups | Engineer (F-Gas certified) | Annual service | Legally restricted; safety and performance |
| Electrical connection inspections | Engineer | Annual service | Prevents faults and fire risk |
| Heat exchanger cleaning/inspection | Engineer | Annual service | Maintains heat transfer efficiency |
| Sensor and control calibration | Engineer | Annual service | Keeps system running to design spec |
| Full performance/COP verification | Engineer | Annual service | Confirms efficiency against original design |
| Compressor and internal component checks | Engineer | Annual service | Flags early wear before breakdown |
What does a recommended heat pump maintenance calendar look like?
A simple way to think about it: homeowner checks are little and often, engineer visits are thorough and annual.
| Who | Frequency | What it covers |
|---|---|---|
| Homeowner | Monthly (year-round, more often in autumn/winter) | Outdoor unit clearance, condensate drain, pressure gauge, app warnings |
| Homeowner | Every 1–3 months, if filter is user-accessible | Filter cleaning per manufacturer instructions |
| Homeowner | Seasonally (start and end of heating season) | Radiator bleeding, indoor unit area check |
| Qualified engineer | Annually | Full service: refrigerant, electrical, heat exchanger, calibration, COP check, compressor |
If your heat pump is still within its manufacturer’s warranty period, typically two to seven years depending on the make, check the specific servicing interval required, as some manufacturers stipulate annual servicing as a strict condition of cover rather than a general recommendation.
What happens if heat pump maintenance gets skipped?
Skip the homeowner-side checks and the most common outcome is a gradual drop in efficiency. A blocked outdoor unit or trapped air in radiators makes the system work harder to hit the same room temperature, which shows up as higher electricity bills long before anything actually breaks. Skip the annual engineer service and the risk shifts from efficiency to reliability: undetected refrigerant leaks, electrical faults and compressor wear are the things that turn into an unexpected breakdown in the middle of winter, plus a voided warranty if a fault is later traced back to a missed service. We cover the full cost and breakdown risk of neglected servicing in more depth elsewhere, but the short version is that the two sides of this maintenance split are complementary. Skipping either one undermines the other.
What does a simple seasonal heat pump maintenance checklist look like?
Break the year into three periods (before winter, during winter, and before/after summer), each with its own short list of tasks, which is a more straightforward way to work through maintenance than trying to remember individual jobs in isolation.
What should you check before winter (September–October)?
- Clear the outdoor unit of summer growth, fallen leaves and any debris
- Check the condensate drain is clear and unobstructed
- Bleed all radiators and check system pressure
- Book your annual engineer service if it isn’t already scheduled
- Check the app for any lingering warning codes before the system’s under heavy use
What should you check during winter (November–February)?
- Check the outdoor unit monthly for snow and ice build-up
- Confirm the condensate drain hasn’t frozen after cold snaps
- Keep clearance around the unit free of stacked snow shovelled from paths and drives
- Monitor the app for warnings, especially after storms or extended sub-zero spells
What should you check before and after summer (March–August)?
- Clear any spring growth, weeds or garden debris from around the outdoor unit
- Rinse user-accessible filters if your model has them
- Check the indoor unit cupboard is still clear and ventilated
- Use the quieter months as the easiest time to get an engineer booked in before autumn demand picks up
Get the split right and a heat pump is low-maintenance from a homeowner’s perspective: a few minutes each month and a straightforward annual booking. Try to save money by skipping the engineer side, though, and you’re taking on both a legal risk and a warranty risk for a job that a certified engineer covers in a single visit. If you’re due a service or want to get one booked in ahead of winter, our engineers cover the full annual check across the UK.
