5 Common Boiler Problems During Hot Weather
Written by Ramin, Manager of VR Central HeatPublished: Updated:
Your heating may be off for summer, but the boiler can still be needed for hot water. Five problems worth watching for are falling pressure, unreliable hot water, visible leaks, repeated shutdowns and controls that do not respond as expected. Hot weather itself is not necessarily the cause; it can simply make faults easier to notice when the heating is used less.
Key takeaways
- Check what the boiler display shows and whether the fault affects hot water, heating or both.
- A pressure drop that keeps returning, a leak or a repeated lockout needs investigation.
- Check accessible settings, but leave internal boiler and gas work to a suitably qualified engineer.
With the radiators off, a hot water fault may become the first sign that something needs attention. The symptoms below can point towards a cause, but they cannot identify a failed component on their own.
1. Boiler pressure keeps dropping
If your boiler shows low pressure or asks you to top it up repeatedly, there may be a leak in the heating circuit or a fault with a component that manages pressure. Look at the gauge or display and note whether the reading falls again after the system has been topped up according to the boiler instructions.
A one-off reading and a continuing loss of pressure are different issues. Repeatedly adding water does not find the cause. Arrange a check if the pressure keeps falling, particularly if you can also see dampness around a radiator valve, pipe or the boiler.
2. No hot water, or hot water that cuts out
On a combi boiler, turning the central heating off for summer should not, by itself, stop hot water at the taps. If the water runs cold, changes temperature or cuts out during a shower, first check whether the issue affects one outlet or every hot tap.
If one tap is affected, the problem may be at that outlet. If all hot taps are affected or the boiler shows a fault code when a tap is opened, the boiler or its controls may need checking. An engineer can test the components involved rather than assuming a particular valve or sensor has failed.
If the whole property has neither heating nor hot water, our no heating or hot water guide covers the wider system question.
3. Water leaking around the boiler
A drip beneath the boiler, staining around nearby pipework or water marks inside a cupboard should be checked. The water might be coming from a joint, valve or another part of the installation; its position alone will not confirm the cause.
Keep clear of any water close to electrical fittings. Do not remove the boiler casing to follow the leak. Record where and when you see water, and arrange a repair assessment. If the boiler is losing pressure as well, mention both symptoms when booking.
4. The boiler keeps switching off
A boiler may stop and display an error or lockout code when it detects a problem. The code is useful information for an engineer, but it does not always tell you which part has failed. Note the code and whether the shutdown happens when a hot tap is opened or when heating is requested.
Follow the user instructions for your boiler if they permit a reset. If it locks out again, stop resetting it and book a check. Repeated shutdowns need a diagnosis of the underlying fault, which may involve pressure, ignition, circulation or controls.
5. Thermostat, timer or programmer problems
If heating comes on unexpectedly in warm weather, check the programmed schedule, thermostat setting and any holiday or manual override mode. If the controls use replaceable batteries, check those too. A wrong setting can look like a boiler fault.
If the display is unresponsive or the boiler ignores the controls despite the settings being correct, the controls or their connection may need investigation. A smart thermostat that is offline has its own set of checks in our smart thermostat connection guide. For work on the controls themselves, see help with smart heating controls.
What can you check before booking?
- Read the pressure gauge and write down any error code.
- Test another hot tap to see whether the issue affects one outlet or the whole property.
- Check the timer and thermostat settings you can access without opening equipment.
- Look for visible water around the boiler and nearby pipework.
- Tell the engineer when the symptom started and whether it returns after a reset.
Keep checks external. Do not remove the boiler casing or attempt to repair a gas appliance. The Health and Safety Executive’s guidance for homeowners says that anyone employed to work on domestic gas appliances must be Gas Safe registered and competent for that type of work.
If the problem is a boiler breakdown, our emergency boiler repairs service is the relevant next step. For a boiler that is working but due its routine check, see boiler servicing and maintenance. A service should not be presented as a substitute for diagnosing an active fault.
Need help with a boiler fault?
If the boiler is losing pressure, leaking, locking out or leaving you without hot water, tell VR Central Heat what you have noticed. Call 020 3633 7807 or use the booking page to request a visit in London.
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