Baxi E133 Fault Code
The E133 fault means the boiler cannot detect a gas supply, or the gas valve has not operated correctly. Do not reset repeatedly — E133 is a gas-related safety lockout.
What is the Baxi E133 fault code?
The Baxi E133 fault is triggered when the PCB detects no gas supply during the ignition sequence, or when the gas valve does not respond within specification. Unlike E168 (which confirms gas is present but ignition failed), E133 indicates the issue is at the gas supply or valve stage — before the ignition sequence can even be completed. This distinction is important: E133 with a confirmed gas supply points directly to the gas valve or PCB.
What causes the E133 fault?
The most straightforward cause — a closed meter valve, empty prepayment meter, or interruption on the local gas network. Always test another gas appliance first.
The gas valve solenoid may not be opening, opening too slowly, or not opening to full flow. A failed gas valve is the most common engineering diagnosis when supply is confirmed.
Loose, corroded, or broken wiring between the PCB and gas valve can prevent the valve from receiving the open command, generating E133 even when the valve is mechanically functional.
A failing PCB may not send the correct signal to the gas valve, or may misread valve position feedback. Diagnosed by elimination after the gas supply and valve are confirmed good.
In rare cases the gas meter itself restricts flow — particularly old diaphragm meters that have not been replaced in 20+ years.
What you can safely check yourself
Turn on a gas hob or fire. If these also have no gas, the supply is the issue — call your gas supplier, not a boiler engineer.
The emergency control valve at the meter should be fully open (handle in line with the pipe). If it was knocked closed, open it and attempt one reset.
Hold the reset button for 3 seconds. If E133 returns, do not reset again. This is a gas-related fault — repeated resets are not safe without diagnosis.
Do not reset the boiler more than once if the fault code returns immediately. Repeated resets without diagnosis can mask a worsening fault.
What needs a Gas Safe engineer
- Confirm gas supply pressure at the meter and boiler inlet
- Test gas valve solenoid resistance and current draw
- Test valve opening and closing response
- Inspect gas valve wiring harness for corrosion or loose connections
- Test PCB gas valve control output if valve and wiring are confirmed good
- Replace gas valve if out of specification
- Commission and gas tightness test after repair
Gas valve failures are not directly linked to hard water, but older housing stock across South London — Wandsworth, Merton, Lewisham, Lambeth, Southwark, Greenwich, and Bromley — means older boilers with more age-related component failures. Baxi Platinum+ and early 600 series boilers from 2008–2014 are at the age where gas valve solenoid wear is common.
How much does a E133 repair cost?
Costs below are UK averages. Reion provides a fixed quote after the £80 diagnostic visit — no obligation to proceed.
How to reset a Baxi boiler showing E133
Test another gas appliance first — if it has no gas, call your supplier, not an engineer.
Check the emergency control valve at the gas meter is fully open.
One reset attempt only — hold for 3 seconds.
If E133 returns, do not reset again. Call a Gas Safe engineer.
If you smell gas at any point, leave the property and call 0800 111 999.
Gas valve replacement runs £280–£460 all in. On a Baxi boiler under 10 years old with no other faults, it is worth doing. On an older boiler with PCB concerns also in play, Reion will give a clear repair-vs-replace assessment.
Common questions about the Baxi E133 fault
What does a Baxi E133 fault code mean?
What is the difference between Baxi E133 and E168?
Is a Baxi E133 fault dangerous?
How much does a Baxi E133 repair cost in London?
Can a Baxi E133 fault be caused by the gas meter?
Other Baxi fault codes
Need a Baxi engineer in London?
Reion is Gas Safe registered (919881), based in South London, and available 24/7. Fixed price after the diagnostic visit — no hidden charges.
