Worcester Bosch GB162 Common Problems & Fault Codes (2026 Guide)

The 6 most common faults

2/3/7 High Engineer

The internal computer board of your boiler has developed a serious fault and can no longer control the heating process.

Est. cost: £300-500
Parts: UBA 3 Control Unit, KIM Identification Module

Full guide for 2/3/7

2/6/7 High Engineer

Your boiler has detected an internal failure within its main control computer, meaning the appliance cannot safely operate and must be shut down.

Est. cost: £300-600
Parts: UBA 3 Control Unit, KIM Identification Module

Full guide for 2/6/7

2/7/2 High Engineer

Your boiler has detected a failure within its main internal computer or communication module, which means the system is unable to safely manage its own controls.

Est. cost: £250-450
Parts: UBA 3 Control Unit, KIM (Key Identification Module)

Full guide for 2/7/2

2/3/8 High Engineer

Your boiler's computer system has encountered an internal technical failure, meaning it can no longer safely operate or heat your home.

Est. cost: £300-600
Parts: UBA 3 Control Unit, KIM (Key Identifier Module)

Full guide for 2/3/8

2/3/9 High Engineer

Your boiler's internal computer is experiencing a major electronic failure, preventing it from starting or maintaining its normal operation.

Est. cost: £300-600
Parts: UBA 3 Control Unit, KIM (Key Coding Interface Module)

Full guide for 2/3/9

2/2/7 High Engineer

Your boiler has failed to light the flame after several attempts and has safely shut itself down to prevent a gas build-up.

Est. cost: £150-300
Parts: Ignition electrode, Flame rectification probe, Gas valve

Full guide for 2/2/7

Parts most often replaced

on the Worcester Bosch GB162

UBA 3 Control UnitKIM Identification ModuleKIM (Key Identification Module)KIM (Key Identifier Module)KIM (Key Coding Interface Module)Ignition electrode

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

You can smell gas or see signs of a leak
The Worcester Bosch shows an Emergency or High severity code
The boiler keeps locking out after repeated resets
You've tried the DIY checks and the fault hasn't cleared
There's visible water leaking from the boiler
The flame is yellow or orange instead of blue

Boiler cover options

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

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.

See the full 47-code list for the Worcester Bosch GB162