In This Guide
What does the Baxi E110 error code mean?
E110 means the boiler has detected that its temperature has climbed past the safe maximum, so it has locked out to protect itself. It is the boiler’s safety thermostat doing its job: rather than keep firing and risk damaging the heat exchanger, the boiler shuts down and shows E110.
Almost every E110 comes down to one of two things. Either water is not circulating through the boiler fast enough to carry the heat away, or a temperature sensor is telling the boiler it is too hot when it is not. Both end in the same lockout, which is why 0800 Homefix treats E110 as a circulation-and-sensor fault to be diagnosed rather than a code to keep clearing.
What causes a Baxi E110 fault?
The common causes overlap, so a methodical check is what separates them:
Cause | What happens | Typical fix |
Low water pressure | Below about 1 bar, water cannot circulate and the boiler overheats | Top up via the filling loop to 1 to 1.5 bar (cold) |
Trapped air | Air pockets block circulation through the radiators | Bleed the radiators |
Sludge or a blocked heat exchanger | Restricted flow creates hot spots that trip the overheat | Power flush |
Failing circulation pump | Water is not moved around the system | Pump repair or replacement |
Faulty thermostat or NTC sensor | A false overheat reading trips the lockout | Sensor or thermostat test and replacement |
Because low pressure and trapped air are the easiest to rule out, start there. Sludge and a failing pump are the usual culprits behind a recurring E110 on an older system, and a power flush is often what clears it for good. The same overheat-from-poor-circulation pattern appears across brands, so if you also run an Ideal boiler our guide to the Ideal L1 overheat and low water flow fault covers the identical mechanism, and the related Baxi circulation fault is explained in our Baxi E125 guide.
What you can check yourself
A few safe checks resolve a good share of E110 faults. Check the pressure gauge and top up via the filling loop if it is below 1 bar. Bleed the radiators to release trapped air. Make sure no radiator or system valves have been left closed. Then reset the boiler once and see if it fires and holds.
If E110 clears and stays clear, it was most likely low pressure or air. What you should not do is keep resetting a boiler that keeps locking out, or attempt work on the pump, thermostat, sensor, or any internal component, as those are engineer tasks and, on a combi, sit inside the sealed boiler casing.
When to call an engineer
If E110 returns after you have corrected the pressure and bled the radiators, the cause is usually sludge, a failing pump, or a faulty sensor, and that needs a Gas Safe registered engineer. Kettling or banging noises, or a boiler that overheats quickly after resetting, also mean it should be looked at rather than run on.
How 0800 Homefix fixes E110 faults
0800 Homefix are Gas Safe registered engineers covering London and the South East, and overheat faults like E110 are everyday work for us. An engineer will confirm whether the cause is circulation or a misreading sensor, fix the actual fault, and check the whole system runs at a safe temperature before leaving. You can see the full service on our boiler repair page, and regular Baxi boiler servicing is the best way to keep sludge and sensor faults from causing the next E110.
0800 Homefix charges as the first hour of labour, paid in advance, with any parts or further work quoted and agreed with you before it begins. For current rates, see our rates page. Our labour is guaranteed for 12 months, and any parts we fit are covered by the manufacturer’s 12-month guarantee.
Frequently Asked Questions
What does the Baxi E110 code mean?
Can I fix a Baxi E110 fault myself?
You can check and top up the pressure, bleed the radiators, confirm the valves are open, and reset once. If E110 returns, the cause is usually sludge, a failing pump, or a sensor fault, which needs a Gas Safe engineer.
Why does my Baxi boiler keep showing E110?
A recurring E110 means the underlying overheat cause has not been fixed. Sludge, a failing pump, and a faulty thermostat or sensor are the most common reasons, and each needs an engineer to resolve.
Is a Baxi E110 fault dangerous?
The lockout itself is the boiler protecting you from overheating, so it is a safeguard. The fault behind it should still be repaired promptly. If you hear kettling or banging, leave the boiler off and call an engineer.
Can I keep resetting my boiler after an E110?
No. A reset may clear it briefly, but repeatedly resetting a boiler that keeps overheating does not fix the cause and can cause further damage.
Helpful resources
- Gas Safe Register: check an engineer is registered to work on your boiler.
- Baxi: official manufacturer support and fault-code information.
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Editorial note: This article is intended as a general homeowner guide. All plumbing work on supply pipes should be carried out by a qualified, WaterSafe-registered plumber. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
