Potterton E133 Fault Code
The E133 fault indicates the boiler cannot detect a gas supply, or the gas valve has not responded correctly during the ignition sequence. Unlike E168 — where gas is present but ignition failed — E133 points to the supply stage before the flame can even be attempted. Do not reset repeatedly. This is a gas-related safety lockout.
What is the Potterton E133 fault code?
The Potterton 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 upstream — the gas valve has not opened or no gas is reaching the boiler. E133 with a confirmed gas supply on other appliances points directly to the gas valve or PCB. Because Potterton shares the BDR Thermea platform with Baxi, this code and its diagnosis are identical across both brands.
What causes the E133 fault?
A closed meter valve, empty prepayment meter, or interruption on the local network. Always test another gas appliance first.
The solenoid may not be opening, or opening too slowly. Most common engineering diagnosis when supply is confirmed on other appliances.
Loose or corroded wiring between PCB and gas valve prevents the valve receiving the open command.
A failing PCB may not send the correct signal to the gas valve. Diagnosed by elimination after testing the valve and wiring.
Old diaphragm meters can restrict flow enough to trigger E133 on a Potterton boiler, even if other appliances are running at low demand.
What you can safely check yourself
Turn on a gas hob or fire. If these also fail, the issue is the supply — call your gas supplier immediately.
Should be fully open (handle in line with the pipe). If knocked closed accidentally, open it and attempt one reset.
If E133 returns, do not reset again. This is a gas-related fault — repeated resets will not help and could indicate a more serious issue. Call a Gas Safe engineer.
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 time
- Inspect gas valve wiring harness for corrosion
- Test PCB gas valve control output signal
- Replace gas valve if out of specification
- Gas tightness test after any repair or valve replacement
Potterton Gold and Promax boilers from 2006–2014 are at the age where gas valve solenoid wear is common. South London's older housing stock in Wandsworth, Merton, Lewisham, Lambeth, Southwark, Greenwich, and Bromley means more age-related component failures on this generation of Potterton boilers. Reion sees E133 most often on Promax models over 12 years old.
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 Potterton boiler showing E133
Test another gas appliance first — if no gas anywhere, call your supplier.
Check the emergency control valve at the gas meter is fully open.
One reset attempt only — hold for 3 seconds.
If E133 returns, 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. On a Potterton boiler under 10 years old, it is worth doing — parts from the BDR Thermea/Baxi platform are widely available. Reion gives a repair-vs-replace assessment for older Promax and Gold models at the diagnostic visit.
Common questions about the Potterton E133 fault
What does a Potterton E133 fault code mean?
What is the difference between Potterton E133 and E168?
Is a Potterton E133 fault dangerous?
How much does a Potterton E133 repair cost in London?
Can a Potterton E133 fault be caused by the gas meter?
Other Potterton fault codes
Need a Potterton 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.
