Low
C.(1) on Potterton Kingfisher 2 RS60, RS80, RS100

Your boiler is not firing up because the thermostat is turned too low or is currently switched off.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Main burner fails to light, pilot burning - Boiler thermostat set to ‘OFF’ or low setting.

Shared across the Kingfisher 2 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This issue occurs because the boiler's internal temperature control is set below the level required to activate the main burner. While the small pilot light remains lit, the boiler effectively thinks it has already reached the desired temperature or has been told to stay off. Adjusting the control knob to a higher number completes the electrical circuit needed to call for heat.

This is frequently seen during the first cold spell of autumn when homeowners forget the boiler thermostat was turned down or off during the summer months.

DIY fix possible

Check the boiler thermostat dial on the front of the unit.Turn the thermostat dial clockwise to a higher setting.Ensure any external room thermostats or programmers are also set to 'ON' and turned up.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

A cover plan would handle faults like C.(1): no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

All 17 fault codes on the Kingfisher 2 RS60, RS80, RS100

Seeing a different code? Every code this model can display, in one place.

Related guides you might find useful