The first cold evening of the year is not the best time to perform your boiler winter checks and find out your boiler has developed an issue. After months of lighter heating use, a system can reveal problems as soon as it is asked to work harder and for longer.
That is why a few checks before the year’s temperatures drop can be worthwhile. From checking pressure and radiators to looking at your condensate pipe and booking a professional service, these simple steps can help you spot potential boiler faults before winter puts your heating system under pressure.
For homeowners across London, Kent and Surrey, we wrap up a list of what to check before winter 2026.
Related: Why Central Heating Issues Often Appear in Winter
1 — Check Your Boiler Pressure
If you have a sealed central heating system, start by looking at the boiler pressure gauge or digital display. The pressure allows water to circulate around the heating system, so an unusually low or high reading can affect how your boiler operates.
- The correct pressure varies between systems and manufacturers, so check your boiler manual rather than relying on a generic figure. Many systems operate within a marked range when cold, but your manufacturer’s instructions should take priority.
A gradual drop in pressure may happen occasionally, particularly after maintenance, but repeated pressure loss deserves attention. Constantly topping up the system without finding the reason can mask an underlying issue, such as a leak or another fault.
If your pressure has fallen outside the recommended range, follow your manufacturer’s instructions if you are familiar with repressurising the system. If you are unsure, or the pressure keeps dropping, it is better to have a qualified heating engineer investigate it.
2 — Inspect Your Radiators And Heating Controls
Turn the heating on and give your radiators time to warm up.
- Are they heating evenly?
- Is one radiator noticeably cooler than the others?
- Do the thermostat and programmer respond when you adjust them?
These simple observations can tell you quite a lot about how your central heating system is performing.
For example, a radiator that is cold at the top but warmer towards the bottom may have trapped air. A radiator that remains cold despite the heating running could have another cause, such as a valve, circulation or system issue.
Your controls deserve attention too.
- A programmer controls when the heating comes on and off.
- Room thermostats regulate the temperature.
- Thermostatic radiator valves (TRVs) allow individual radiators to be adjusted according to the needs of each room.
Modern heating controls can help prevent unnecessary heating by matching your system to your routine. Energy Saving Trust recommends setting a room thermostat to the lowest comfortable temperature, which is generally around 18°C to 21°C for most people.
Bleed Radiators If They Are Cold At The Top
If the top of a radiator stays cold while the lower part becomes warm, trapped air could be restricting circulation. Bleeding the radiator releases that air and can help restore more even heating.
Let the radiator cool first and use the correct radiator key. You should also check the system pressure afterwards, as bleeding radiators can affect it.
If a radiator repeatedly develops cold spots, however, bleeding it may not solve the underlying problem. Sludge, poor circulation or balancing issues can also affect radiator performance. That is where a professional assessment can save you from repeatedly treating the symptom rather than the cause.
Related: How to Bleed a Radiator the Easy Way
Test Your Thermostat And Heating Schedule
Before winter arrives, check that your thermostat is reading and responding correctly and that your heating schedule still matches your household routine.
Heating an empty house for hours simply because the programmer has been left on an old schedule is not a very practical way to save energy. Likewise, turning the thermostat higher does not make a boiler heat the house faster; it simply sets a higher target temperature.
If your existing controls are dated or awkward to use, smart heating controls may be worth considering. They can provide remote control and more flexible scheduling, although their value depends on how you currently use your heating.
3 — Look For Signs Of Boiler Trouble
A boiler that appears to be working can still give warning signs that something is not quite right.
- Listen for unusual banging, whistling, or kettling noises.
- Look out for repeated fault codes, unexplained shutdowns, inconsistent hot water, frequent pressure loss.
- Check for visible leaks around the heating system.
None of these symptoms should automatically be treated as a diagnosis. A strange noise can have several possible causes, for example, and repeatedly resetting a boiler does not resolve whatever caused the fault in the first place.
If you smell gas or suspect a gas leak, do not attempt to investigate or repair the appliance yourself. Follow the relevant UK gas emergency guidance, and only book for a Gas Safe registered engineer to fit, fix or service your gas appliances.
4 — Check Your Boiler Service History
When was your boiler last professionally serviced?
If you cannot remember, check previous invoices, service records or paperwork supplied with the appliance. If you have recently moved into the property, it is also worth finding out what information is available about the boiler’s maintenance history.
A service is different from a repair. A repair responds to a known fault, while servicing involves checking the appliance and its operation as part of routine maintenance. Make sure to arrange your boiler service before the busiest part of winter provides useful peace of mind. It also gives an engineer an opportunity to identify issues that may not be obvious from normal day-to-day use.
5 — Keep Boiler And Heating Vents Clear
One of the very important boiler winter checks that you can do yourself is taking a look around your boiler and any visible ventilation openings. Has anything been placed in front of them since your last heating season?
Furniture, storage and household items should not obstruct ventilation openings or interfere with the boiler’s flue arrangements.
This is a visual check, not an invitation to dismantle or alter anything. Do not attempt to modify the boiler, flue or ventilation system yourself. If something looks damaged, obstructed, or different from how you remember it, ask a qualified engineer to assess it.
6 — Protect Your Condensate Pipe From Freezing
Modern condensing boilers produce condensate as part of their normal operation. This acidic wastewater is discharged through a condensate pipe, which may run from the boiler to an external drain.
- During prolonged freezing weather, an exposed condensate pipe can freeze. If the discharge becomes blocked, the boiler may shut down and display a fault.
Before winter, check the visible external section for obvious damage and make sure it has appropriate insulation in line with the manufacturer’s guidance. If you have experienced frozen condensate problems before, it is worth raising this with a heating engineer before the next cold spell.
7 — Consider Whether Your Boiler Is Ready For Winter 2026
After all these boiler winter checks, remember that not every older boiler needs replacing simply because it has reached a certain age. Condition, reliability, repair history, efficiency, and the availability of parts all matter.
However, if your boiler has become increasingly unreliable or you are repeatedly paying for repairs, winter is a good time to consider whether continued maintenance still makes sense for your household.
If replacement is on the table, the right boiler is not simply the one with the highest output or the latest features. Consider:
- your property’s size;
- hot-water demand;
- number of bathrooms; and
- the existing pipework and heating system.
For example, a combi boiler can be a practical choice for many homes because it heats domestic hot water on demand without a separate cylinder. Larger properties with greater simultaneous hot-water demand may have different requirements, making a system or regular boiler with a hot-water cylinder worth considering.
On the other hand, modern condensing boilers can be considerably more efficient than older boilers because they recover heat from flue gases that would otherwise be lost.
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8 — Book A Professional Boiler Service Before Winter
Once you have completed your own checks, the final step is knowing when to hand things over to a professional.
A qualified engineer can assess the boiler and heating system more thoroughly than a visual homeowner check can. This is particularly worthwhile if you have noticed pressure problems, unusual noises, recurring faults or inconsistent heating.
For gas boilers, use a Gas Safe registered engineer with the appropriate qualifications for the work being carried out.
A professional service, however, is not a guarantee that an older boiler will make it through every winter without a fault. What it does provide is a more informed picture of the appliance’s condition, allowing you to deal with problems before they become an unexpected cold-weather breakdown where possible.
Get Winter-Ready With Rowlen Boiler Services
A few straightforward boiler winter checks can give you a better idea of how your heating system is performing before the colder months arrive. Check the pressure, test your controls, look over the radiators, inspect accessible areas around the boiler, and pay attention to anything that seems different from normal.
If your checks reveal a problem, or your boiler is due for a professional service, our team can help. At Rowlen, we’ve been proud to serve generations of families across London, Kent and Surrey for over five decades, bringing the personal approach of a family-run business together with the expertise of Gas Safe registered engineers.
Whether your home needs boiler servicing, repairs, central heating work or a new boiler installation, we can assess the property and discuss the practical options with you. The aim is simple: a heating system that is properly suited to your home, professionally installed and ready to work when you need it most.
Contact us today!
