High
F13 on Vaillant ecoMAX Pro 28E

Your boiler's computer brain has encountered a serious communication error and can no longer control the heating system safely.

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

Main board fault

From this model's manual
Verified against the Vaillant/Vaillant Ecomax Pro 28e installation & service manual, page 26.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal computer experiences a major electrical short or a critical component failure on the control board. The most common reason is general wear and tear of the electrical circuits over time, or pulse damage caused by a power surge.

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 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.

All 29 fault codes on the ecoMAX Pro 28E

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

F.1F.4F.5F.6F.10F.11F.12F.13F.17F.20F.24F.25F1F4F5F6F10F11F12F14F16F17F18F19F20F24F25F26

Related guides you might find useful

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 →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →