High
OVERHEAT LOCKOUT on Potterton Promax FSB 30HE

Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage to its internal components.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Lights: On Off * Off. Possible causes: Flow pipe thermostat (stat) failure, fan stat failure, thermistor (red sensor on flow pipe) failure, combustion chamber door seal damaged, or PCB failure.

From this model's manual
Verified against the Potterton/Potterton Promax Fsb 30he 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.

Engineer required

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

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 OVERHEAT LOCKOUT: 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 Promax FSB 30HE

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

Burner On (Green Light)CONDENSATE PUMPCondensate Pump (Green Light)E06 058E06 059E06 060FAN LOCKOUTFlame Failure (Red Light)Flow SwitchIgnition LockoutMains On (Green Light)On * * OffOn * On OffOn Off * *On Off On OffTHERMISTOR

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 →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →