When the heating stops in a British winter, you want two answers fast: is this something I can fix myself, and is it safe? This hub covers the most common boiler and heating problems in UK homes, from low pressure and lockout codes to cold radiators, with clear steps and honest advice about when you need an engineer.
Never remove a boiler's casing or work on gas pipes, flues or the burner. By law, gas work must be done by a Gas Safe registered engineer. If you smell gas, call the National Gas Emergency number on 0800 111 999 immediately, turn off the gas at the meter if it's safe to do so, open windows, and don't use switches or flames.
Start here: the most-needed fixes
- What should my boiler pressure be? (And how to top it up)
- Combi boiler losing pressure: 6 causes and what to do
- What does L2 mean on a boiler? Ignition lockout explained
Boiler pressure
What the gauge should read, how to top up with a filling loop, and why pressure keeps dropping or rising.
HeatingBoiler Leaking Water? Causes, What to Do Now and Repair CostsA boiler leaking water needs attention, but it's rarely an emergency. What to do right now, the common causes, and what repairs cost.5 min readRead
HeatingCombi Boiler Losing Pressure? 6 Causes and How to Fix ThemIf you're topping up your boiler every week, something's wrong. The six common causes, what you can check yourself, and what needs an engineer.6 min readRead
HeatingVaillant F22 Fault Code: What It Means and How to Fix ItF22 on a Vaillant boiler means there isn't enough water pressure in the system. Here's how to top it up and reset it, and what to do if F22 keeps coming back.7 min readRead
HeatingWhat Should My Boiler Pressure Be? (And How to Top It Up)What your boiler gauge should read hot and cold, how to top up a combi boiler using the filling loop, and what to do if the pressure is too high.7 min readRead
Boiler fault codes
What each code means on Worcester Bosch, Ideal, Baxi, Vaillant and other popular UK boilers, whether it's safe to reset, and what to try first.
HeatingWhat Does L2 Mean on a Boiler? Ignition Lockout ExplainedL2 means your boiler tried to light and failed. The usual causes, from a frozen condensate pipe to no gas, and how to reset it safely.7 min readRead
HeatingVaillant Boiler Fault Codes: Complete List (F22, F28, F75 and More)Every common Vaillant fault code in one place: what it means, whether you can fix it yourself, and how to reset your boiler safely.5 min readRead- HeatingVaillant F22 Fault Code: What It Means and How to Fix ItF22 on a Vaillant boiler means there isn't enough water pressure in the system. Here's how to top it up and reset it, and what to do if F22 keeps coming back.7 min readRead
HeatingVaillant F28 Fault Code: Boiler Not Firing Up? Here’s the FixF28 means your Vaillant boiler tried to light and failed. The common causes, from no gas to a frozen condensate pipe, and how to reset it safely.6 min readRead
HeatingHow to Reset a Worcester Boiler (and What a Flashing Blue Light Means)How to reset a Worcester Bosch boiler on every popular Greenstar model, what a flashing blue light means, and what to do when the reset doesn't work.7 min readRead
Boilers: buying, costs and problems
Which boiler you have, what a new one costs, the best brands, and odd noises and leaks.
Radiators
Bleeding, balancing, cold spots, valves and symbols, and choosing the right size.
Guides in progress. Our editor is researching this topic now.
Request a guide →Radiator BTU calculator
An estimate for choosing radiator size. Radiator outputs are listed at ΔT50; heat pumps run cooler, so radiators need roughly double the ΔT50 rating. For a new system, ask your installer for a room-by-room heat loss calculation.
Thermostats and smart controls
Hive, Nest, Tado and traditional thermostats: setup, comparisons and the settings that save money.
Guides in progress. Our editor is researching this topic now.
Request a guide →Hot water and immersion heaters
Cylinders, immersion heaters, timers and what they cost to run.
Guides in progress. Our editor is researching this topic now.
Request a guide →Underfloor heating
Electric vs wet systems, running costs, and retrofitting on concrete or timber floors.
Guides in progress. Our editor is researching this topic now.
Request a guide →Heat pumps
Air source heat pump costs, grants, running costs and whether your radiators need upgrading.
Guides in progress. Our editor is researching this topic now.
Request a guide →FAQs
Can I reset my boiler myself?
Yes. Pressing the reset button is designed for householders and is safe. If the boiler locks out again soon after, stop resetting it and call a Gas Safe engineer, because repeated lockouts mean a fault needs diagnosing.
Is it safe to top up boiler pressure myself?
Yes, using the filling loop is a normal householder job, covered in your boiler's user manual. If you need to top up more than every few weeks, there's a leak or a faulty part to find.
How often should a boiler be serviced?
Once a year by a Gas Safe registered engineer. It keeps the boiler safe and efficient, and most manufacturers require it to keep the warranty valid. Landlords must also have gas appliances safety-checked every year.