Bosch fault code b2/b3/ b4/b5/b6
Fault code b2/b3/ b4/b5/b6 on a Bosch boiler (including Turbo Tower) means: Internal data error. Reset the appliance once. If the code comes back, a part is usually faulty. You can check the water pressure and settings yourself; leave work on gas-carrying parts to a certified gas engineer.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code b2/b3/ b4/b5/b6 on a Bosch boiler indicates: Internal data error.
Applies to
Bosch Turbo Tower, 30 HRC, 30 HRC II, TOP, 28-3 ZSB, 30-3 ZWB, 42-3 ZB, 42-3 ZWB.
Matching parts
Bosch parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
This message does not point directly to one faulty part. These are the parts that most often fit this appliance:
- Nefit flue sleeve € 8.50
- Nefit fan gasket € 11.76
- Nefit sealing ring inspection hatch € 13.07
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does Bosch boiler fault code b2/b3/ b4/b5/b6 mean?
Internal data error.
How do I fix fault code b2/b3/ b4/b5/b6 on a Bosch boiler?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for Bosch fault code b2/b3/ b4/b5/b6?
That depends on the exact cause. In the Bosch parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code b2/b3/ b4/b5/b6 myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All Bosch boiler faults and codes at a glance →