E006 on a Viessmann Vitocal 100-A: Flow alarm (blocks: Machine)
Short answer
On a Viessmann heat pump, E006 means: Flow alarm (blocks: Machine). The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Flow alarm (blocks: Machine).
Part involved: Flow alarm.
When it shows: The water side flow switch is already installed inside the unit and MUST NOT be tampered with or bypassed in any way. The flow switch is bypassed for 10 seconds after the unit is switched on. When the bypass time has elapsed, you must evaluate ….
Likely causes:
- The water side flow switch is already installed inside the unit and MUST NOT be tampered with or bypassed in any way. The flow switch ….
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: Auto-resets per s.13 when condition clears; manual reset required if triggered more than 3 times/hour.
Manual reset: Placing the controller in OFF mode resets alarms and hour counters (6167577 s.13, printed p.34); if alarms persist when switched on, contact technical assistance.
What you can check
- Note the E-code (e.g. E006) shown on the Vitocal 100-A controller display and give it to your installer.
- Per 6167577 s.13, switching the controller to OFF resets alarms; if the alarm is still present when switched back on, stop and contact your installer/Viessmann technical assistance (do not keep cycling it).
- Check the heat pump breaker/isolator in the consumer unit is ON and the outdoor unit is not blocked by leaves, debris or snow.
- Check the heating system pressure gauge and make sure the filling loop is closed.
What the engineer will check
- Check water flow, pump and flow switch (must not be tampered with or bypassed).
- Read alarm log (Hist) on controller; contact Viessmann technical assistance if alarm persists.
Who to ask for: Viessmann-trained heat pump installer/service engineer.
What you might notice
Sources
- Installation/service instructions Vitocal 100-A outdoor unit controller (6167577, 9/2020) ↗ · 6167577 VSA00001 · page 36 (PDF p.38) table 13.2; detail s.13.1 printed p.34-35 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026