UK trade guideBoiler Spares 4 min readUpdated 10 July 2026

How to Fix Potterton E133 Fault Code (UK)

Potterton showing E133 — Ignition failure. UK diagnosis, likely spare (spark electrode) and step-by-step reset.

Potterton

What the code means

E133 on a Potterton indicates ignition failure. The boiler locks out to protect the heat exchanger and, on gas faults, to comply with the Gas Safety (Installation and Use) Regulations. Always reset to confirm the code is live, not historical.

Likely spare

The most common fix is the spark electrode. Check the exploded diagram against the GC number on the data plate before ordering — Potterton revised parts on Potterton units mid-production.

Fix procedure

Same PCB as Baxi. Check spark, gas, electrode.

Log the fault and reset. If the code returns within 24 hours, escalate to full electrical diagnosis with a manometer and multimeter.

Frequently asked questions

Can I reset E133 myself?
You can press the reset button up to 3 times. If E133 returns, the boiler needs a Gas Safe engineer — it is illegal to repair gas components without registration.
Is the part covered under warranty?
Potterton standard warranty is 2–10 years depending on model. Registered installations get the full term. Check the sticker inside the case.
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