What does the Potterton B. (1) fault code mean?

Your boiler's pilot light isn't staying lit because the gas supply isn't being held open long enough during the ignition process.

How much does it cost to fix Potterton error code B. (1)?

Typical repair cost for the Potterton B. (1) fault is £120-250 including labour.

Main burner fails to light and pilot is extinguished when pressure on the control knob is released - Control knob not held down long enough.

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Older boilers — thermocouple, draught, gas supply.

Lockout fault with a reset-needed pattern.

Safety-critical — turn off, read this.