Potterton E167 Fault Code: Causes, Fixes & Repair Costs
What does the Potterton E167 fault code mean?
The E167 code on a Potterton boiler signals that the boiler's Printed Circuit Board (PCB) has detected an internal electrical fault and shut the appliance down as a safety measure. The PCB acts as the boiler's control centre — it orchestrates ignition, regulates temperature and pressure, and communicates with every sensor and component in the system. When the board itself malfunctions, or when a fault elsewhere in the wiring confuses its signals, the E167 code is the result. Because the PCB touches almost every part of the boiler, this fault can cause complete shutdowns, erratic behaviour, or repeated lockouts. This code is most commonly seen on Potterton Promax and Performa models and always requires a Gas Safe registered engineer to diagnose and rectify properly.
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
- PCB internal failure Common
The PCB itself has developed an internal electrical fault — this can happen through normal wear over time, component degradation, or manufacturing defect. Signs often include a flickering or blank display, random lockouts, and fault codes that reappear immediately after reset. On older Potterton boilers this is the most frequently confirmed cause of E167.
- Water or moisture ingress Common
A small internal leak from a heat exchanger, pump seal, or pipework joint can drip onto the PCB over time, corroding tracks or short-circuiting the board. Water damage is a leading reason why PCBs fail prematurely and is often only discovered when an engineer opens the casing and inspects the board directly.
- Loose or damaged wiring connections Sometimes
Faulty wiring can mimic a full PCB failure. Corroded terminals, chafed cables, or connectors that have worked loose can disrupt the signals the PCB relies on and trigger E167 without the board itself being damaged. Engineers should always check wiring thoroughly before condemning the PCB.
- Faulty sensor sending incorrect signals Sometimes
Sensors such as the flame detector, thermistor, or pressure sensor can develop faults that send garbled data to the PCB, causing it to raise an internal error. Replacing a single sensor is considerably cheaper than a PCB, so this possibility should be ruled out during diagnosis.
- Power surge damage Rare
A spike in the mains electricity supply — for example during a local lightning strike or a sudden power restoration after a cut — can damage the PCB and sometimes other electrical components such as the ignition module simultaneously.
How to fix it
- Attempt a boiler reset DIY safe
Locate the reset button on your Potterton boiler's control panel and hold it for approximately 3–5 seconds until the boiler attempts to restart. If the E167 code clears and the boiler runs normally, monitor it closely over the next 24 hours. If the fault returns promptly, do not keep resetting repeatedly — two or three attempts is the sensible limit before calling for professional help.
- Check for obvious signs of a water leak near the boiler DIY safe
Look around the base of the boiler, behind the casing, and along visible pipework for any damp patches, dripping water, or corrosion stains. Do not attempt to open the boiler casing yourself, but note any visible wetness and report it to your engineer — it can help them locate the source of PCB damage quickly.
- Confirm the mains power supply is stable DIY safe
Check that the boiler's isolation switch is firmly on and that no fuses or circuit breakers related to the boiler have tripped. If a recent power cut or surge preceded the fault, let your engineer know — this information helps them assess whether surge damage is involved.
- Arrange a professional diagnostic inspection Gas Safe engineer
A Gas Safe registered engineer should attend to test the PCB outputs individually using appropriate diagnostic equipment. They will also inspect all wiring looms, connectors, and sensors before reaching a conclusion. This step is critical — replacing the PCB without ruling out a faulty sensor or damaged wiring can mean an expensive unnecessary swap.
- PCB repair or replacement by a Gas Safe engineer Gas Safe engineer
If the PCB is confirmed as faulty, the engineer will source a replacement board compatible with your Potterton model. On Promax and Performa ranges, parts availability is generally good. The engineer will fit, configure, and test the new PCB to confirm the boiler operates safely across all functions before leaving the property.
Parts you may need
- Replacement PCB (Potterton Promax / Performa compatible) · from £260
- Flame sensing electrode · from £25
- NTC thermistor (flow or return) · from £20
- Wiring loom / harness · 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 £350–£600, depending on the underlying cause.
Frequently asked questions
Can I fix a Potterton E167 fault myself?
No — this is not a DIY repair. The only homeowner steps worth trying are a single boiler reset and a visual check for visible leaks or tripped switches. The PCB is an electrical component at the heart of the boiler, and any work on it must be carried out by a Gas Safe registered engineer. Attempting repairs yourself could invalidate your warranty, damage other components, or create a safety hazard.
How much does it cost to fix an E167 fault in the UK?
Most homeowners pay between £350 and £600 all-in, which covers the engineer's diagnostic visit, a replacement PCB (typically £180–£300 for the part alone on Potterton models), and labour. Engineers in London and the South East tend to be at the top of that range; those in the North of England, Scotland, or Wales are often 10–20% cheaper. Note that if the fault turns out to be a faulty sensor or loose wiring rather than the PCB itself, the bill can be considerably lower — sometimes under £150. In rare cases where additional components were also damaged (for example by a power surge), costs could exceed £600, but this is uncommon.
Is it worth replacing the PCB on an older Potterton boiler?
It depends on the boiler's age and overall condition. If the boiler is under 8–10 years old and has been serviced regularly, a PCB replacement is often good value and can restore several more years of reliable use. For boilers over 12–15 years old, it is worth asking your engineer whether other components are showing wear — if the repair cost exceeds roughly half the price of a new boiler, replacement is usually the more economical long-term choice.
Why does my Potterton boiler keep showing E167 even after I reset it?
A fault that returns immediately or within a short time after reset almost always means the underlying problem has not been resolved. The most likely explanations are a genuinely failed PCB, ongoing water ingress that continues to affect the board, or a faulty sensor sending persistent bad signals. Repeated resetting will not fix any of these issues and could mask a worsening problem — the right step is to book a Gas Safe engineer for a proper diagnosis.