How much does it cost to fix a Baxi boiler fault?

£80 for the first hour of repair labour plus any parts at trade price. Most common Baxi faults are diagnosed and fixed in the first visit because we carry the regular parts on the van (fans, gas valves, expansion vessels, sensors, PCBs). The diagnosis fee is also £80 — the same as the first hour — and it counts towards the repair if you go ahead. No separate call-out fee.

Can I reset my Baxi boiler myself?

Yes, but only once. Modern Baxi boilers lock out permanently after roughly five resets in a short window. If the code returns after one reset, the cause needs diagnosing — not resetting. Repeated resets do not fix the underlying fault and can make some faults more expensive to repair.

How quickly can BASI come out for a same-day Baxi repair?

Same-day where we can across BD, LS, WF, HD, HX and HG postcodes when you call in the morning. Otherwise next-day. Out-of-hours emergency cover is by phone on 0800 980 6018.

Will an annual service prevent Baxi fault codes?

Often, yes. A lot of common Baxi faults (E110 overheat, E125 water flow, E133 ignition lockout) become much more likely as the boiler ages and the system gets dirty. An annual £80 service keeps it clean, checks gas pressure and combustion, and catches small problems before they lock you out on a cold morning.

Are BASI a Baxi-approved installer?

No. BASI is not a Baxi-approved installer — our accredited install brands are Worcester Bosch and Vaillant. But we service and repair Baxi boilers across Yorkshire; you do not need a Baxi-approved badge for service or repair, you need a Gas Safe engineer who knows the boiler and carries the parts.

Baxi Boiler Fault Codes Explained

If your Baxi boiler has stopped and is showing a code, this guide explains what it means, whether there is anything safe you can do yourself, and when you need a Gas Safe engineer. These codes apply across the modern Baxi range (Duo-tec, Megaflo, Platinum, 600 and 800 series); the older F-series codes apply to the 400 / 600 / Solo families.

Before you do anything else: if you can smell gas, do not touch the boiler. Leave the building, leave the door open, and call the National Gas Emergency line on 0800 111 999.

Quick fault-code reference

Code	What it means	What to do
E10	Outdoor temperature sensor fault (Megaflo / Duo-tec)	Often the sensor or its cable. Usually a cheap fix once an engineer is on site.
E110	Overheat / overheat thermostat tripped	Check the pressure gauge sits at 1 to 1.5 bar. If you have just topped it up, try one reset. If the code returns, call a Gas Safe engineer; the cause is often a stuck pump or sludge restricting circulation.
E125	No water flow / circulation issue	Check radiators are getting hot evenly. A cold radiator or one cold side often means an air-lock or pump issue. Try bleeding the radiators. If the code returns, call an engineer; the system may need a power flush.
E133	Gas valve / ignition lockout	Check other gas appliances (hob, fire) are working. If they are not, the gas supply is the issue — call the National Gas Emergency line. If they are, try one reset. If the code returns, call a Gas Safe engineer; do not reset repeatedly.
E160	Fan fault	The flue fan is not running correctly. Do not reset repeatedly. Call a Gas Safe engineer; a fan replacement is usually 60-90 minutes.
E168	Generic lockout — needs a diagnostic	The boiler has locked out and the cause is not specific enough for the on-board diagnostics to name. Try one reset; if the code returns, call an engineer with a combustion analyser.
E199	Boiler temperature sensor fault	Sensor or wiring. Requires a Gas Safe engineer.
E50 / E51	Flue, condensate or air-pressure switch	In cold weather a frozen condensate pipe is the usual culprit. Our frozen condensate guide explains the safe thaw. If clear and warm, call an engineer.
F1 / F4	Older Baxi 400 / 600 / Solo codes — pressure or sensor faults	The pressure gauge and filling loop work the same way as modern boilers; re-pressurise to 1-1.5 bar and reset once. If the code returns or your boiler is pre-2010, parts can be harder to source; book an engineer.

E110 — overheat: what to check before you call

E110 fires when the overheat thermostat trips, which usually means heat is building up in the boiler because water isn’t moving through it properly. The most common causes:

Low pressure. The gauge should sit at around 1 to 1.5 bar when the heating is off. If it’s lower, re-pressurise using the filling loop and try one reset.
Sludge in the system. A boiler nearing 10 years old with no recent power flush is the classic candidate. The fix is a power flush, not a repair.
A stuck pump. The pump should be warm to the touch when the heating is calling for heat. If it’s cold or buzzing, it’s the pump.
Closed valves. Make sure all radiator valves and the system bypass are open.

If pressure is fine and the radiators are heating evenly but E110 keeps appearing, the underlying cause needs a Gas Safe engineer.

E133 — gas / ignition lockout: what to do

E133 is the boiler telling you it tried to light and could not, or it lit and lost the flame. Before you call:

Check other gas appliances. If your hob and fire are not working either, the issue is the gas supply itself; call the National Gas Emergency line on 0800 111 999.
If only the boiler is affected, try ONE reset. Press the reset button once and wait for the boiler to fire.
Do not reset more than once. The boiler locks out for safety reasons; repeated resets can mask a real fault.
If the code returns, call a Gas Safe engineer. The cause is usually the gas valve, the ignition lead, the flame sensor or the PCB.

E125 — no water flow

E125 means the boiler cannot detect water moving through it. Things you can try:

Bleed your radiators. Air in the system stops water moving. Our guide to bleeding radiators walks through it.
Check radiator valves are open. Particularly the lockshield (the cap end) on any radiator that has been worked on recently.
Check the system pressure. Below 1 bar can stop circulation; top up using the filling loop.

If the radiators are bleeding clear water, valves are open and pressure is fine, the cause is almost always the pump (worn, stuck or seized) or a partially blocked heat exchanger from sludge. Both require an engineer.

The reset rule

Modern Baxi boilers will lock out permanently after roughly five resets in a short window. If you have already pressed reset twice without success, stop. The boiler is telling you the cause needs diagnosing, not resetting. Repeated resets do not fix the underlying fault and can make some faults more expensive to repair.

Frozen condensate in cold weather

In a cold snap, the condensate pipe (a white plastic pipe running from the boiler to an outside drain) can freeze and back the boiler up. The symptoms are often E50, E51 or the boiler just gurgling and shutting down with no clear code. Our frozen condensate pipe guide explains the safe thaw, which is something you can usually do yourself in fifteen minutes.

When to book an engineer

Call us if:

You have tried one reset and the code returns
The boiler is making unusual noises (banging, kettling, whistling)
You see water leaking from the boiler or pipework
The code is one we have marked above as “call a Gas Safe engineer”

Book a £80 Baxi repair online or call us on 0800 980 6018. Same-day where we can across BD, LS, WF, HD, HX, HG postcodes when you call in the morning.

Stop the next breakdown before it happens

A lot of the codes above (E110, E125, E133) get more likely as the boiler ages and the system gets dirty. An annual £80 boiler service keeps the system clean, checks the gas pressure and combustion, and catches small problems before they lock you out on a cold morning. If you would rather pay monthly and stop thinking about it, our Smart Care cover plans cover any boiler brand including Baxi.

Baxi boiler fault codes, explained