BD on a Viessmann Vitotronic 200: KM BUS remt. ctrl HC2: No room temperature-dependent con-; No room temperature hook-up for trol for heating circuit with mixer M2. heating circuit with mixer M2
Short answer
On a Viessmann heat pump, BD means: KM BUS remt. ctrl HC2: No room temperature-dependent con-; No room temperature hook-up for trol for heating circuit with mixer M2. heating circuit with mixer M2. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: KM BUS remt. ctrl HC2: No room temperature-dependent con-; No room temperature hook-up for trol for heating circuit with mixer M2. heating circuit with mixer M2.
Part involved: KM BUS remt. ctrl HC2.
When it shows: No room temperature-dependent con-; No room temperature hook-up for trol for heating circuit with mixer M2. heating circuit with mixer M2.
Likely causes:
- Communication fault KM BUS remote control heating circuit with mixer M2.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: Not stated per code; Vitotronic messages remain until the cause is removed and are acknowledged with OK (6150133 p.82). Unremedied acknowledged faults are redisplayed the following day.
Manual reset: Acknowledge with OK on the programming unit (user level permitted per 5817913 p.56-57) after the cause is remedied.
What you can check
- Note the 2-character message code and message text shown on the Vitotronic 200 display (press OK for details) and give them to your heating contractor (operating instructions 5817913 p.56).
- You may acknowledge the message once with OK as described in the Vitotronic 200 operating instructions; if it reappears, do not keep acknowledging it - call your contractor.
What the engineer will check
- Check heating circuit allocation, connections and remote control cable.
Who to ask for: Viessmann-trained heat pump installer/service engineer.
What you might notice
Sources
- Service instructions Vitotronic 200 heat pump control unit (5692896, 2011-02) – 222-G/242-G/242-S/333-G/343-G/350-A ↗ · 5692896 VSA00001 · page 62 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026