Common problems guide

The most common Viessmann Vitodens 200-W B2HA-49 problems

The faults most likely to send a Viessmann Vitodens 200-W B2HA-49 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

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

The 6 most common faults

01
F9 High Engineer

Your boiler's fan isn't starting, so it can't safely run the burner, which means it has shut itself down and is likely not giving you heating or hot water until a qualified engineer looks at it.

Est. cost
£200-450
Parts
Fan assembly, Fan connecting cable or harness, Fan control PCB (main board)
Full guide for F9
02
EE High Engineer

Your boiler has stopped because it could not light its burner safely, so it has shut itself down to protect your home and it will not heat your water or radiators until a qualified engineer checks it.

Est. cost
£120-350
Parts
Ignition electrode, Ignition module, Ionisation electrode
Full guide for EE
03
38:≠0 High Engineer

Your boiler has stopped its burner from working properly, so it may not be producing heat or hot water until a qualified engineer checks it.

Est. cost
£120-400
Parts
Burner control unit (PCB), Ionisation (flame sensor) electrode, Ignition electrode
Full guide for 38:≠0
04
30 High Engineer

The boiler has shut itself down because its burner is being blocked by a faulty temperature sensor, so it is not producing heat or hot water until a qualified engineer checks it.

Est. cost
£150-250
Parts
Boiler water temperature sensor (NTC), Sensor wiring harness or plug connector, Control circuit board (PCB), if the short circuit has caused damage
Full guide for 30
05
38 High Engineer

Your boiler has shut itself down as a safety precaution because it has lost track of the water temperature, so it needs a qualified engineer to check the sensor and its wiring.

Est. cost
£120-220
Parts
Boiler water temperature sensor (NTC), Sensor wiring lead or connector, Flow temperature sensor
Full guide for 38
06
50 High Engineer

The boiler's sensor that measures the temperature of your hot water cylinder is sending a faulty reading, so the boiler may not heat your stored hot water properly until it's repaired.

Est. cost
£100-200
Parts
Cylinder temperature sensor, Sensor wiring harness, Boiler control PCB (only if the sensor and wiring test good)
Full guide for 50
Parts most often replaced

on the Viessmann Vitodens 200-W B2HA-49

Fan assemblyFan connecting cable or harnessFan control PCB (main board)Gas valve (if the fan fault has damaged it)Ignition electrodeIgnition module

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 82-code list for the Viessmann Vitodens 200-W B2HA-49

Related guides

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