Low
Flashing Mains ON light on Potterton Performa System HE

Your boiler is receiving power, but it has been turned off at the main control dial.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Indicates that there is a mains electrical supply to the boiler, but the control knob is in the OFF position.

From this model's manual
Verified against the Potterton/Potterton Promax System Erp installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Locate the main control dial on the front of the boiler panelTurn the dial clockwise away from the 'OFF' or '0' position to your desired heating or hot water setting

Find a Gas Safe engineer
Search the official register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like Flashing Mains ON light: 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 24 fault codes on the Performa System HE

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

1011122021232425MAINS LED FLASHINGMAINS LED OFFneon flashingneon flashing (Section B)neon flashing (Section C)neon flashing (Section E)neon flashing (Section H & K)neon flashing (Section I)neon flashing (Section J)neon flashing (Section M)neon illuminatedneons flashing (Section D)Overheat Stat neons flashingPressure of 3 or greaterReset neon does not extinguish

Related guides you might find useful

Boiler won't turn on — 9-step checklist

Work through these before the call-out.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →