200-w und B7 und pressure/druck - Page 1
km1967: 10.07.2026
200-w und B7 und pressure/druck
Hello
Englisch and Deutch
DEU: My 6-year old Vitodens 200-W stopped with error code B7. I pressed R to reset, but same error returned. I then powered off, approx 15 minutes, and then on again. Same error again, but on pressing R this time the boiler came up and is now working. However, I notice the pressure is barely more than 0.5 bar. Sadly I dont know what it was in years before, and whether this relates to the B7 issue. What should I do now, if anything?
ENG: Meine sechs Jahre alte Vitodens 200-W hat mit dem Fehlercode B7 den Betrieb eingestellt. Ich habe zunächst die R-Taste zum Zurücksetzen gedrückt, jedoch erschien derselbe Fehler erneut.
Anschließend habe ich die Heizung für etwa 15 Minuten vollständig ausgeschaltet und danach wieder eingeschaltet. Zunächst wurde der Fehler erneut angezeigt, doch nachdem ich diesmal erneut die R-Taste gedrückt hatte, startete der Kessel wieder und funktioniert seitdem. Mir ist allerdings aufgefallen, dass der Anlagendruck nur knapp über 0,5 bar liegt. Leider weiß ich nicht mehr, wie hoch der Druck in den vergangenen Jahren normalerweise war und ob dies möglicherweise mit dem Fehler B7 zusammenhängt.
Was sollte ich Ihrer Meinung nach jetzt tun? Muss ich etwas unternehmen?
Vielen Dank im Voraus für Ihre Unterstützung.
divanc: 10.07.2026
Betreff: 200-w und B7 und pressure/druck
Hello @km1967
Error B7 is unrelated to low water pressure in the heating system.
For now, you can ignore the error message; however, if it recurs, please let us know so we can provide instructions on the next steps.
The system pressure is usually 1.5 bar, so top up the water.
Next time, please also include the boiler model designation (e.g., B2HB) so we can assist you more easily.
Best regards
km1967: 10.07.2026
Betreff: 200-w und B7 und pressure/druck
thanks for response and advice. Can you please send me link to the English language manuals, I have only the (paper) German ones dated 07/2019, which was about 3-4 months before the boilers were installed, and which were supplied by the vendor at that time.
The book given with boiler is marked Vitodens 200-W Typ B2HB / B2KB. The kessel number is 7570782... (can send full number if you need it).
I am not 100% sure how to fill/top up as I've never done this before. There is large water tank (COSMO speicher) and a COSMO MAG-H (we have underfloor heating if it matters, no radiators).
Below are some fotos.
divanc: 11.07.2026
Betreff: 200-w und B7 und pressure/druck
Hello @km1967
Top up the water in the system by partially opening both filling valves on the flexible hose shown in the photo. Based on the boiler's serial number, it is intended for the German market, so the documentation is only in German.
I am also attaching the requested instructions for the English market, although they may not perfectly match your specific boiler.
Best regards,
divanc: 11.07.2026
Betreff: 200-w und B7 und pressure/druck
Hello @km1967
The user manual is also included.
Best regards,
km1967: 11.07.2026
Betreff: 200-w und B7 und pressure/druck
Yep, this is what I thought, just wanted to be sure. I am in Bavaria, so that that its a German market is of course correct. I'm OK with the German manuals, but English is my native language so thanks for the docs too.
When I'd opened both valves and let pressure gauge increase to ca:, 1.5, it had dropped back to ca: 1.0 when I closed one valve again. It is now at around 1.2. it got closer to 2.0, but as soon as I closed one again it again drops by around 0.5 bar. Dunno if this is normal. Both valves back in the original position now obviously.
I will see if this pressure holds over coming days, and if B7 comes back. Currently, and since around May, the boiler is only feeding the hot water tank, heating it around 3 hours per day. The central heating is (as is usual here) off for the summer. I am more used to the combi / on-demand boiler style which are more common in UK, and usually the filling loop valves are ... closer to the bloiler itself.
Thanks a LOT for your help/advice.
