Potterton E134 Fault Code: Causes, Fixes & Repair Costs
What does the Potterton E134 fault code mean?
The E134 fault code appears when the boiler's PCB (printed circuit board) has sent the signal to open the gas valve, but the boiler cannot confirm that gas is actually reaching the burner. Because the boiler cannot establish a flame within the allowed time window, it locks out as a safety precaution. This is sometimes described as 'elapsed time gas valve open without gas' — essentially the boiler tried to fire, waited, and detected nothing. Do not repeatedly reset the boiler; if the underlying cause has not been fixed, the lockout will simply repeat, and persistent resets on a gas-flow fault carry a safety risk.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Gas supply or pressure problem Common
If the gas pressure feeding the boiler is too low — whether at the meter, the pipework, or the final connection to the boiler — the burner will not receive enough gas to ignite. A Gas Safe engineer can measure pressure at multiple points (inlet to meter, outlet from meter, and at the appliance) to pinpoint exactly where the supply is failing. Other gas appliances in your home cutting out at the same time is a useful clue.
- Stuck or incorrectly adjusted gas valve Common
The gas valve may be physically stuck in the closed position, or its calibration may have drifted enough that gas flow to the burner is insufficient even when the valve is technically open. An engineer will check both the electrical signal being sent to the valve and the valve's mechanical response. In some cases a simple recalibration is all that is needed — no replacement parts required.
- Faulty gas valve Sometimes
If the valve cannot be recalibrated and is found to be defective, it will need to be replaced. Gas valves are not typically stocked on an engineer's van and usually need to be ordered from a plumbing merchant, so same-day completion is unlikely. The repair is a well-established one for Potterton Promax and Performa models with good parts availability.
- Faulty or misfiring PCB Rare
The PCB controls when and how the gas valve opens. If the board is sending incorrect or intermittent signals, the valve may not respond correctly — and the PCB may then misread the situation, triggering E134. Engineers will test individual PCB outputs and check wiring connections before concluding the board itself needs replacing, since a loose or damaged wiring loom can produce identical symptoms.
How to fix it
- Check your other gas appliances DIY safe
Turn on a gas hob ring or check another gas appliance in the property. If nothing is working, the issue is likely with the mains gas supply rather than the boiler itself. In that case, contact your gas network operator (e.g. Cadent, SGN, or Wales & West Utilities) rather than a boiler engineer.
- Check the gas isolation valve on the boiler supply pipe DIY safe
Locate the gas isolation valve on the pipe leading into the boiler — when the slot is parallel to the pipe, the valve is open; when it is perpendicular, it is closed. Ensure it is fully open. Do not touch any other valves or gas fittings.
- Attempt a single reset DIY safe
If the gas supply appears normal, press and hold the reset button (or follow the reset procedure in your boiler's user guide) once. Allow the boiler to run through its ignition sequence. If it fires and runs normally, monitor it over the next 24 hours. If it locks out again, do not keep resetting — move to the next step.
- Call a Gas Safe registered engineer to diagnose the fault Gas Safe engineer
If the boiler locks out again after one reset, or if you have any doubt about the gas supply, contact a Gas Safe registered engineer. They will carry out gas pressure tests, inspect the gas valve electrically and mechanically, check PCB outputs, and advise whether adjustment, a valve replacement, or a PCB replacement is needed. You can verify an engineer's Gas Safe registration at gassaferegister.co.uk.
Parts you may need
- Gas valve (Potterton Promax / Performa compatible) · from £175
- PCB (printed circuit board) · from £220
- Wiring loom / harness · from £45
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £200–£420, depending on the underlying cause.
Frequently asked questions
Can I reset the boiler myself when E134 appears?
You can try a single reset to see whether it was a one-off ignition failure, but that is as far as a homeowner should go. If the boiler locks out again with E134, do not keep pressing reset. Repeatedly restarting the boiler when gas flow is not being confirmed is a safety risk, and the root cause — whether a pressure issue, a stuck valve, or a PCB fault — will not resolve itself through resetting.
How much does it cost to fix a Potterton E134 fault?
Most people pay somewhere between £200 and £420 for a diagnosis and repair, depending on what the engineer finds. A gas valve recalibration at the lower end of the scale costs relatively little beyond the callout and labour. A gas valve replacement typically adds up to around £300 all-in for parts and labour. A PCB replacement can reach £450–£550 and is worth weighing against the age and overall condition of the boiler — if other major components are also showing wear, a new boiler may be more cost-effective.
Is E134 the same fault on all Potterton boilers?
The E134 code carries the same fundamental meaning across Potterton's gas boiler range — the PCB opened the gas valve but detected no gas flow. However, the specific gas valve part number, its location, and the PCB design vary between models such as the Promax, Promax Store, Performa, and Titanium. Always give your engineer the full model name and serial number so they can source the correct components.
Should I replace my boiler rather than repair it when E134 appears?
It depends on the boiler's age and wider condition. If the fix is a valve recalibration or a straightforward valve swap and the rest of the boiler is in good shape, repair is usually the better value. If the engineer also finds issues with the pump, fan, heat exchanger, or other expensive parts, the combined repair cost may approach or exceed the cost of a new, more efficient boiler. Ask your engineer to give an honest assessment of the boiler's overall condition before committing to an expensive repair.