Common problems guide

The most common Viessmann Vitodens 200-W B2KA-30 problems

The faults most likely to send a Viessmann Vitodens 200-W B2KA-30 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

83 documented codes
6 most common
1 DIY-safe checks
5 engineer needed

The 6 most common faults

01
F9 High Engineer

The boiler's internal fan is not starting when it needs to, so it has stopped and is unable to heat your home or water safely until it is checked by an engineer.

Est. cost
£200-400
Parts
Fan assembly, Fan connecting cable, Fan control PCB (main board)
Full guide for F9
02
EE High Engineer

The boiler tried to switch on but could not detect a flame, so it has stopped as a safety precaution and will need a qualified engineer to find out why.

Est. cost
£100-400
Parts
Ignition and ionisation electrode, Gas valve (gas train), Gas filter
Full guide for EE
03
E3 High DIY-safe

Your boiler has paused because it could not finish a self-check of how it burns gas, which usually happens when it cannot get rid of its heat fast enough, and a simple reset often gets it running again.

What to try first

Check the boiler pressure gauge. It should read between 1 and 1.5 bar when cold. If it is low, top it up using the filling loop, then close the loop valves.Make sure all radiator valves and any heating zone valves are open, and turn off any thermostatic valves that might be blocking flow, so the boiler has somewhere to send its heat.Press the reset button marked R once and wait 10 to 15 minutes while the boiler runs its calibration. If the fault returns or the boiler stays locked out, stop and call a Gas Safe registered engineer.

Est. cost
£90-180
Parts
Combustion fan, Gas valve, Control PCB
Full guide for E3
04
Eb High Engineer

Your boiler has paused while it sets up its internal settings for burning gas safely, and it needs a reset and a check by a qualified engineer to finish the job.

Est. cost
£120-260
Parts
Ionisation electrode, Burner gauze assembly, Burner gasket
Full guide for Eb
05
30 High Engineer

Your boiler has stopped heating because a sensor that measures the water temperature has sent a faulty signal, so it has shut itself down as a safety precaution.

Est. cost
£120-220
Parts
Boiler water temperature sensor (NTC thermistor), Sensor wiring harness or connector, Main PCB control board (if the sensor fault has damaged the board)
Full guide for 30
06
38 High Engineer

Your boiler has shut itself down because it cannot read the temperature of the water it is heating, so it is stopping the burner as a precaution.

Est. cost
£120-220
Parts
Boiler flow temperature sensor, Sensor wiring lead or connector, Control PCB (only if the sensor and wiring test good)
Full guide for 38
Parts most often replaced

on the Viessmann Vitodens 200-W B2KA-30

Fan assemblyFan connecting cableFan control PCB (main board)Ignition and ionisation electrodeGas valve (gas train)Gas filter

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
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 83-code list for the Viessmann Vitodens 200-W B2KA-30

Related guides

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