DC on a Viessmann Vitotronic 200: Low pressure 2: Compressor heat pump stage 2 stops
Short answer
On a Viessmann heat pump, DC means: Low pressure 2: Compressor heat pump stage 2 stops. 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: Low pressure 2: Compressor heat pump stage 2 stops.
Part involved: Low pressure 2.
When it shows: Compressor heat pump stage 2 stops.
Likely causes:
- Low pressure fault, heat pump stage 2 (if installed):.
- Heat pump faulty.
- Primary pump faulty.
- Low pressure switch has responded.
- Low pressure sensor has issued a fault message.
- Low pressure sensor faulty.
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.
- Check the heating system pressure gauge reading and report a low reading to your contractor; make sure the filling loop is closed.
What the engineer will check
- Have heat pump checked by a refrigeration engineer.
- Check pressure gauge, primary pump and shut-off facilities.
- Check low pressure sensor, lead and EEV PCB; replace if necessary. The signal at plug aYH can be measured at connection 214.3 (see "Main PCB"). ….
- Appliances with low pressure sensor : Jumper set across terminals 116.3/116.4. Signal must be permanently present (230 V~).
- Appliances with low pressure switch : No jumper across terminals 116.3/116.4. There is no signal if the pressure switch has responded (0 V).
Who to ask for: Viessmann-trained heat pump engineer with F-gas refrigeration certification.
Certification: F-gas certificate (UK F-gas Regulations; Viessmann: refrigerant work by authorised refrigeration engineers only).
Sources
- Service instructions Vitotronic 200 WO1C (5790974 GB, 2023-09) – brine/water & split variants ↗ · 5790974 VSA00002 · page 90-91 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026