Andrews E15 Fault Code: Causes, Fixes & Repair Costs
What does the Andrews E15 fault code mean?
The E15 code on an Andrews boiler indicates that the boiler's electronic controls have detected a problem with the gas valve circuit — meaning the valve isn't opening, closing, or responding as it should. As a safety measure, the boiler locks out and stops the ignition sequence entirely, preventing gas from reaching the burner until the fault is resolved. Andrews boilers sit within the Baxi Group family, so E15 carries the same meaning across related Baxi-platform products.
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
- Faulty or seized gas valve Common
The gas valve can seize in either the open or closed position. If it sticks closed, no gas reaches the burner and the boiler cannot light. If it sticks open, gas may continue to pass through even when the boiler is off — a dangerous condition known as 'letting by'. A seized valve is the most common root cause of E15 on Andrews boilers.
- Loose or damaged wiring to the gas valve Common
The wiring harness connecting the PCB to the gas valve can suffer from loose terminals, corrosion, or vibration-related wear over time. When these connections are intermittent or broken, the PCB cannot reliably send or confirm commands to the valve, triggering the E15 lockout. You may notice the fault appearing and disappearing unpredictably before it becomes permanent.
- PCB (printed circuit board) fault Sometimes
The PCB is responsible for sending the electrical signals that open and close the gas valve in response to heating and hot water demand. If the PCB develops a fault — whether due to component failure, moisture ingress, or power surge damage — it may send incorrect signals or none at all, causing the boiler to report E15 even when the valve itself is in good physical condition.
How to fix it
- Check for a gas supply issue DIY safe
Before assuming the boiler is at fault, confirm that your gas supply is working. Check whether other gas appliances in your home (such as a gas hob) are functioning normally. If there is no gas supply to the property, contact your gas supplier rather than an engineer.
- Reset the boiler (up to two or three times only) DIY safe
Press and hold the reset button on your Andrews boiler as described in the user manual — typically for around 3 seconds until the display changes. Wait for the boiler to complete its start-up sequence. If the E15 code returns immediately or after a short time, do not keep resetting. Repeated resets without addressing the underlying fault can override safety protections and create a hazardous situation.
- Do not attempt to inspect or adjust the gas valve yourself Gas Safe engineer
The gas valve is a safety-critical component carrying high-pressure combustible gas. Inspection, testing, and replacement must only be carried out by a Gas Safe registered engineer using calibrated equipment. There is no homeowner-safe action involving the valve itself.
- Call a Gas Safe registered engineer to inspect wiring and connections Gas Safe engineer
An engineer will visually inspect the wiring harness between the PCB and the gas valve, check each terminal for corrosion or looseness, and use a multimeter to test continuity and resistance. Damaged wiring or faulty connectors will be repaired or replaced. This is often the quickest and least expensive resolution.
- Gas valve electrical testing and pressure checks Gas Safe engineer
If wiring checks out, the engineer will measure the voltage being supplied to the gas valve solenoid and verify gas inlet and burner pressures using calibrated gauges. This confirms whether the valve is receiving the correct signal and responding appropriately, or whether it has failed internally.
- Replace the gas valve if required Gas Safe engineer
If the valve is found to be seized, letting by, or non-responsive despite receiving correct electrical signals, it will need to be replaced with a compatible unit. After fitting, the engineer will re-test gas pressures and carry out a full functional check before leaving the appliance in service.
- PCB replacement if the valve is not the root cause Gas Safe engineer
Should the gas valve and wiring both test as satisfactory, the PCB is the likely culprit. The engineer will test the PCB outputs, and if faulty, replace the board. PCB replacement is one of the more expensive repairs, so a good engineer will only recommend it once other causes have been ruled out.
Parts you may need
- Gas valve (Andrews/Baxi compatible) · from £185
- PCB (printed circuit board) · from £260
- Wiring harness/loom · from £45
- Gas valve solenoid coil · from £55
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 £120–£380, depending on the underlying cause.
Frequently asked questions
Can I fix the Andrews E15 fault code myself?
No. The E15 code relates directly to the gas valve circuit, which involves high-pressure gas components. Homeowners are limited to checking the gas supply is on and attempting a reset no more than two or three times. All further diagnosis and repair must be carried out by a Gas Safe registered engineer. Attempting to work on the valve or PCB yourself is both illegal for gas components and genuinely dangerous.
How much does it cost to fix an Andrews E15 fault?
Most homeowners pay between £120 and £380 depending on what needs attention. A wiring or connection repair sits at the lower end (around £120–£180 including labour), while a gas valve replacement typically comes in at £180–£280 all-in for a standard job. PCB replacement tends to be the most expensive common repair at £250–£380. Note that if your boiler is still under warranty, the valve or PCB replacement may be covered — always check before booking an engineer.
Is it safe to keep resetting the boiler when E15 appears?
No. You should try a reset once or twice to see if the fault clears after a transient glitch, but if E15 returns, stop resetting and call an engineer. Repeatedly resetting a boiler with an active gas valve fault can override the safety lockout and create a potentially hazardous situation. If you ever smell gas, do not reset the boiler — turn off the gas at the mains isolator (the yellow lever beside your meter) and call the National Gas Emergency Service on 0800 111 999 immediately.
Why does the Andrews E15 code appear on Baxi boilers too?
Andrews is a commercial boiler brand within the Baxi Group, and many Andrews models share their core control architecture with Baxi-platform products. As a result, the E15 gas valve command fault code carries the same meaning across these related ranges. If you see E15 on a Baxi-platform boiler, the diagnostic approach and likely causes are identical to those described on this page.