High limit thermostat High

Firebird High limit thermostat Fault Code

Also written as HIGHLIMITTHERMOSTAT — same fault.

The Firebird High limit thermostat fault code means: your boiler has detected that it has become dangerously hot and has automatically shut itself down to prevent damage, requiring a manual reset.. It appears on 1 Firebird model 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: High limit thermostat indicator light. Safety system fixed at 114˚C that shuts the boiler off in the event of the control thermostat failing; requires the limit button to be pushed to restart.
Typical repair cost £120-250 (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 High limit thermostat: 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.

Firebird models that show the High limit thermostat fault code

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

Source

Firebird High limit thermostat fault code information on this page is sourced and cross-checked against the official Firebird service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026