What does the Glow-worm 18 fault code mean?

Your boiler's main control panel has lost communication with the internal system, meaning your settings or commands aren't being processed correctly.

How much does it cost to fix Glow-worm error code 18?

Typical repair cost for the Glow-worm 18 fault is £180-350 including labour.

Glow-worm 18 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Local user interface fault

From this model's manual

Verified against the Glow Worm Cxi Csi System installation & service manual, page 37.

What causes this fault?

This fault occurs when the digital connection between the boiler's display screen and the main internal brain is broken. The most common reason is a loose or damaged wiring connection between the two components, though it can also be caused by an electrical failure on one of the circuit boards themselves.

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 18: 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.

Your boiler's main control panel has lost communication with the internal system, meaning your settings or commands aren't being processed correctly.

What the manual says

What causes this fault?

Engineer required

Avoid the next call-out bill

Related guides you might find useful

Yellow or orange flame — CO safety

When to replace your boiler

Is boiler cover worth it?

Recently viewed