Boiler playing up? Let's diagnose it together.
Free troubleshooting guides for the most common boiler faults — plus a searchable database of fault codes for Worcester Bosch, Baxi, Ideal and Vaillant.
Quick-fix troubleshooting guides
Six issues we see every week.
Low boiler pressure (below 1 bar)
Pressure gauge dropped below 1 bar. Boiler may have shut down or radiators are cold at the top.
Low boiler pressure (below 1 bar)
Pressure gauge dropped below 1 bar. Boiler may have shut down or radiators are cold at the top.
Try this first
- 1Turn the boiler off and let it cool.
- 2Find the filling loop — usually a silver braided flexible pipe under the boiler.
- 3Slowly open both valves until the pressure gauge reads between 1.2 and 1.5 bar.
- 4Close both valves tight, then turn the boiler back on and reset if needed.
Still stuck? If pressure keeps dropping after re-pressurising, you likely have a leak somewhere in the system. Give us a call.
No heating but hot water works
Hot water at the tap is fine, but radiators stay cold.
No heating but hot water works
Hot water at the tap is fine, but radiators stay cold.
Try this first
- 1Check the room thermostat — battery dead or set too low?
- 2Make sure the boiler is set to 'Heating + Hot Water'.
- 3Check the timer/programmer is calling for heat.
- 4Bleed any radiator that's cold at the top.
- 5Check pressure gauge is between 1.0 and 1.5 bar.
Still stuck? Still no heat? Likely a stuck diverter valve, a seized pump or a control board fault — book a Gas Tech engineer.
No hot water (but heating works)
Radiators warm up fine, but the taps run cold.
No hot water (but heating works)
Radiators warm up fine, but the taps run cold.
Try this first
- 1Check the boiler's hot-water dial isn't set to 0 / Eco-off.
- 2Run a tap for 60 seconds — combi boilers fire on flow.
- 3If the boiler doesn't fire when a tap is on, there's a flow-sensor or diverter-valve issue.
Still stuck? Diverter valves and flow sensors are common combi-boiler faults. Most are a quick fix.
Frozen condensate pipe (winter lockout)
Boiler shows a fault code after a cold night — common in Lancashire winters.
Frozen condensate pipe (winter lockout)
Boiler shows a fault code after a cold night — common in Lancashire winters.
Try this first
- 1Find the white plastic pipe that exits your boiler outside (usually 22mm).
- 2Pour warm — not boiling — water along the pipe to thaw any ice.
- 3A hot-water bottle wrapped around the pipe also works.
- 4Reset the boiler once the pipe is clear.
Still stuck? Pipe keeps freezing? It probably needs lagging or rerouting indoors. We can sort that in a single visit.
Banging, gurgling or kettling noises
Your boiler or radiators sound like a kettle, banging pipes, or gurgling.
Banging, gurgling or kettling noises
Your boiler or radiators sound like a kettle, banging pipes, or gurgling.
Try this first
- 1Sludge build-up is the usual cause — your system needs a powerflush.
- 2Bleed any noisy radiators (especially gurgling ones).
- 3Check pressure is between 1.0 and 1.5 bar.
Still stuck? Persistent banging or kettling means the heat exchanger is scaled up. Book a powerflush before it kills the boiler.
Boiler leaking water
Water dripping from the boiler casing or pipework underneath.
Boiler leaking water
Water dripping from the boiler casing or pipework underneath.
Try this first
- 1Switch off the boiler at the spur fuse.
- 2Turn the heating off at the programmer.
- 3Place a bucket / towels under the leak.
- 4Note where the water is coming from.
Still stuck? A leaking boiler should never be left running. Call us — we'll diagnose and fix it the same day in most cases.
Boiler error codes — what they mean & what to do
Common fault codes for the four most-installed boiler brands in Lancashire.
No flame detected / ignition failure
Check gas supply is on; thaw condensate pipe; if it returns after reset, call us.
Overheat — primary thermostat tripped
Usually a pump or flow issue; do not keep resetting — book an engineer.
Low system pressure
Re-pressurise to 1.2 bar via filling loop. Keeps dropping? Leak — call us.
Fan or air-pressure switch fault
Engineer visit needed — fan replacement is common.
Flue or condensate blockage
Check condensate isn't frozen; otherwise call us.
Don't keep resetting a boiler that keeps locking out.
Repeated resets can cause expensive damage. If a fault returns after one reset — let us take a look.
Still stuck? We'll come and look.
Free fixed-fee diagnostics across Lancashire — usually same-day.