Low
F13 on Ferroli Leb TS

Your boiler is struggling to read the temperature outside, which may cause it to run less efficiently or prevent the heating from adjusting correctly.

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

Outdoor temperature sensor faulted (faulted NTC sensor, short circuited cables, unconnected cables, or interrupted cables).

From this model's manual
Verified against the Ferroli Leb Ts installation & service manual, page 7.
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 fault requires 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 F13: 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.

Related fault codes

F14View →

Related guides you might find useful

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 →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →