Most boiler breakdowns we see around Wigan come down to the same handful of faults, and several of them give clear warning signs before the heating stops. This guide explains what those signs mean, which ones you can safely check yourself, and when to leave it alone and call a Gas Safe registered engineer.
Look at the pressure gauge on the front of your boiler. With the heating off and cold, it should sit between about 1 and 1.5 bar. If it has dropped below roughly 0.5 bar, most combi boilers will refuse to fire and show a low pressure code, such as F22 on a Vaillant, E119 on a Baxi or F1 on an Ideal Logic.
Topping up through the filling loop is something your manual will show you how to do, and a one-off top up after bleeding radiators is normal. If you are topping up every few weeks, though, water is going somewhere. The usual causes are a weeping radiator valve, a leak on pipework under the floor, a failed expansion vessel or a pressure relief valve that is letting by. Check the small copper pipe that exits the outside wall near the boiler: if it is dripping, mention that when you ring.
A lockout is the boiler shutting itself down because something is not right. It is a safety feature, not a nuisance. The code on the display narrows down the cause, although the same code can have several possible triggers.
Pressing reset once is reasonable. If the boiler locks out again, stop resetting it and note the code, because repeated resets can mask a fault that is getting worse.
Water in the Wigan area is generally soft, so heavy limescale is less of a problem here than in other parts of the country. What we see far more often is sludge: black iron oxide that builds up in older steel radiators and pipework. Many of the terraces and semis in places like Pemberton, Ince, Hindley and Swinley still have radiators that are 25 or 30 years old, connected to a much newer boiler.
Sludge shows up as radiators that are hot at the top and cold along the bottom, a boiler that rumbles or bangs like a kettle, and a pump that gets noisy. Radiators cold at the top simply need bleeding. Gurgling usually means trapped air, which often goes hand in hand with low pressure.
Every condensing boiler has a plastic pipe that carries waste water to a drain. Where that pipe runs along an outside wall, it can freeze solid on a hard frost, and the boiler will gurgle and then lock out. We get a run of these calls every winter, particularly from exposed properties and homes where the boiler is in a garage or loft.
You can thaw the pipe yourself by pouring warm, not boiling, water along it from ground level, then resetting the boiler. If it keeps happening, the pipe can be rerouted indoors, upsized or insulated.
Bleeding radiators, topping up pressure and thawing a condensate pipe are fine for a homeowner. Anything that involves removing the boiler casing is not, and by law gas work must be done by a Gas Safe registered engineer. If you smell gas, turn off the supply at the meter, open windows and ring the National Gas Emergency line on 0800 111 999.
Costs depend on the make, the age of the boiler and how easy parts are to get. As a rough guide locally, a diagnostic visit is typically £60 to £100. Common repairs such as a fan, pump or diverter valve usually fall between £200 and £400 fitted, and a circuit board can run from £250 to £500. On a boiler over 12 to 15 years old, it is worth asking for an honest view on whether the repair is good value before going ahead.
Published 10 October 2026 by Red Leaf Plumbing & Heating.
Call Luke for a free, no-obligation quote. Family-run, Gas Safe, hassle-free.
Wigan-based, family-run plumbing and heating specialists. Get in touch with Luke for a free, no-obligation quote on any boiler, heating or plumbing work.
