Common problems guide

The most common Viessmann Vitodens 200-W B2KB-35 problems

The faults most likely to send a Viessmann Vitodens 200-W B2KB-35 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

89 documented codes
6 most common
0 DIY-safe checks
6 engineer needed

The 6 most common faults

01
EE High Engineer

The boiler has paused because air has got into the gas supply pipe, which is common during setup and usually clears with a single reset, but it may need a gas engineer to purge the line if it keeps happening.

Est. cost
£80-150
Parts
Gas line purge and recommissioning (labour only, usually no parts), Gas valve (only if purging does not resolve the fault)
Full guide for EE
02
F9 High Engineer

The boiler's internal fan is not running properly, so it keeps trying to start and then shuts itself down as a safety precaution, which usually means you'll have no heating or hot water until a engineer checks it.

Est. cost
£250-450
Parts
Fan assembly, Fan connecting cable, Fan control PCB
Full guide for F9
03
81/EE High Engineer

Your boiler tried to light its burner but couldn't keep a flame going, so it has shut down as a safety measure and is probably not providing heating or hot water until it's checked.

Est. cost
£150-350
Parts
Ignition electrode, Ignition module (ignition unit), Gas valve
Full guide for 81/EE
04
80/EE High Engineer

Your boiler has stopped because it is not receiving the gas it needs to start, so it cannot currently provide heating or hot water.

Est. cost
£150-350
Parts
Gas valve (gas train), Gas filter, Gas pressure switch
Full guide for 80/EE
05
82/EE High Engineer

The boiler started up to heat your home but could not detect a steady gas flame, so it has stopped as a safety precaution and will need a reset and a check of the burner.

Est. cost
£90-220
Parts
Ionisation and ignition electrode assembly, Electrode gasket or seal, Gas valve (if the gas supply or valve is faulty)
Full guide for 82/EE
06
E3 High Engineer

Your boiler has stopped because its burner settings need recalibrating, which usually means a Gas Safe engineer needs to check it, though a simple reset may get it running again for now.

Est. cost
£120-350
Parts
Combustion fan, Gas valve, Ignition electrode
Full guide for E3
Parts most often replaced

on the Viessmann Vitodens 200-W B2KB-35

Gas line purge and recommissioning (labour only, usually no parts)Gas valve (only if purging does not resolve the fault)Fan assemblyFan connecting cableFan control PCBGas valve

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 Viessmann 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
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See the full 89-code list for the Viessmann Vitodens 200-W B2KB-35

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →