Boiler
102
If your Potterton boiler is displaying error code 102, it has detected a problem with the flame signal — specifically, it’s either failing to light or losing the flame shortly after ignition. This fault can leave you without heating or hot water, and while it can sometimes be resolved with a simple reset, it often points to a component that needs professional attention. In this guide, we’ll walk you through exactly what the code means, the most likely causes, what you can safely do yourself, and when it’s time to call a Gas Safe registered engineer.
What does this error mean?
Error code 102 on Potterton boilers (including popular models such as the Potterton Assure, Performa, and Titanium ranges) indicates a flame failure or ignition fault. In plain terms, your boiler is trying to light the burner but either the flame isn’t establishing at all, or it lights briefly and then cuts out within a few seconds. The boiler’s control board monitors the burner flame via a component called the flame sensing electrode (or ionisation probe). When this sensor doesn’t detect a stable flame within a set time window — usually a few seconds — the boiler locks out and displays code 102 as a safety precaution. This is the boiler protecting itself and your home from a potential gas or combustion issue, so it should never be ignored or repeatedly overridden.
Est. repair cost
£90–£180 for a Gas Safe engineer call-out and flame sensor or ignition electrode replacement; £200–£350 if the gas valve requires replacement; £300–£500+ for a PCB fault on an older model
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 – Reset the boiler: Press and hold the reset button (usually marked with a flame or reset symbol on the boiler’s front panel) for 3–5 seconds, then release. Wait 2–3 minutes for the boiler to go through its startup sequence. This is the only truly safe DIY step for a gas boiler fault — if the error clears and the boiler runs normally, monitor it over the next 24 hours.
Step 2 – Check your gas supply: Before assuming the boiler is faulty, verify that other gas appliances in your home (such as your gas hob) are working normally. If they are not, you may have a gas supply issue — call your gas supplier or the National Gas Emergency Service on 0800 111 999 immediately.
Step 3 – Check that the gas service valve is fully open: Locate the gas isolation valve on the pipe leading into the boiler (it’s usually a quarter-turn lever valve). Ensure it is parallel to the pipe, meaning it is fully open. If it has been accidentally knocked to a partially closed position, this alone can cause a 102 fault.
Step 4 – Inspect the condensate pipe for freezing (in winter): If the error code 102 appears during very cold weather, check your condensate pipe — typically a white plastic pipe exiting through an outside wall. If it feels solid or you can hear gurgling, it may be frozen. You can carefully thaw it by pouring warm (not boiling) water over the pipe, then reset the boiler. This is one of the few external checks a homeowner can safely perform.
Step 5 – Do not attempt further DIY: All remaining causes of error code 102 — including cleaning or replacing the flame sensor, testing or replacing ignition electrodes, inspecting the gas valve, or examining the PCB — involve working on gas-carrying components or internal boiler parts. Under UK Gas Safety (Installation and Use) Regulations 1998, only a Gas Safe registered engineer is legally permitted to carry out this work. Attempting it yourself is illegal, dangerous, and will invalidate your boiler warranty and home insurance. Stop here and call a professional.
📞 When to call a professional
You should call a Gas Safe registered engineer if: the boiler fails to reset after one or two attempts; the error code 102 returns within a short period after resetting; your other gas appliances are working fine (ruling out a supply issue); or you’ve confirmed the condensate pipe is clear and the service valve is open. When you call, tell the engineer: ‘My Potterton boiler is showing error code 102, which I understand is a flame failure fault. I’ve tried resetting it [number] times and checked the gas supply and condensate pipe, but the fault keeps returning.’ This information helps the engineer arrive prepared with the most likely replacement parts — typically a flame sensing electrode, ignition electrode, or gas valve — saving you time and a potential second call-out. Do not repeatedly reset the boiler in an attempt to clear the fault, as this can cause unburnt gas to accumulate and may cause further damage to the heat exchanger or PCB.
⚖️ Repair or replace?
For a Potterton boiler showing error code 102, the repair decision largely depends on the age of the boiler. Potterton is a well-established UK brand (part of the Baxi group), and spare parts for most models in the Assure, Performa, and Titanium ranges are readily available through merchants like Wolseley, Plumbase, and online suppliers. **If your boiler is under 8 years old:** Repair is almost always the right call. A flame sensing electrode costs around £15–£30 for the part alone; an ignition electrode is similar. A gas valve is more expensive (£80–£150 for the part), but still well worth replacing on a relatively young boiler. **If your boiler is 8–12 years old:** Get the repair done, but start budgeting for a replacement within the next few years. Ask the engineer for an honest assessment of the boiler’s overall condition while they’re there. **If your boiler is over 12–15 years old:** Weigh the repair cost carefully. A new A-rated combi boiler typically costs £1,800–£3,000 installed in the UK (2024 prices), but you’ll benefit from improved efficiency (potentially saving £200–£300/year on energy bills), a fresh manufacturer’s warranty (typically 5–10 years), and no further repair bills in the short term. If the engineer quotes over £400–£500 for a repair on a boiler that age, replacement is usually the more sensible long-term investment.