Flash Off On High

Potterton Flash Off On Fault Code

Also written as FLASHOFFON — same fault.

The Potterton Flash Off On fault code means: your boiler has detected that it reached a dangerous temperature and has safely shut itself down to prevent damage.. It appears on 2 Potterton models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Overheat Lockout. Go to Overheat Lockout section of the fault finding instructions.
Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like Flash Off On: 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.

Potterton models that show the Flash Off On fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Potterton Flash Off On fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026