S.277 on a Vaillant heat pump: Building circuit: Pump fault If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restarted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is switched off and the …
Short answer
On a Vaillant heat pump, S.277 means: Building circuit: Pump fault If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restarted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is switched off and the …. The heat pump keeps running with some functions stopped. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 2 sources
What it means
On the aroTHERM plus (VWL ../6 A)
The manual says: Building circuit: Pump fault If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restarted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is switched off and the ….
Part involved: Heat pump control (status/Live Monitor).
When it shows: Building circuit: Pump fault If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restarted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is switched off and the ….
Likely causes:
- Building circuit: Pump fault If the building circuit pump is inactive, the heat pump is switched off for 10 minutes and is then restarted. If the building circuit pump does not start up after three unsuccessful restarts, the heat pump is switched off and the ….
On the flexoTHERM exclusive (VWF ../4)
The manual says: Building circuit: Pump fault.
Part involved: Heat pump control (status/Live Monitor).
When it shows: See official description.
Likely causes:
- Building circuit: Pump fault.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Warning |
The heat pump keeps running with some functions stopped.
Resetting itself: yes - status changes automatically with operating state.
Manual reset: not applicable.
What you can check
- Note the status code (Live Monitor). The heat pump will normally retry automatically; if a related F-code appears or heating/hot water stops, contact your installer.
What the engineer will check
- Read Live Monitor status and fault history; if the status persists or precedes an F-code, follow the corresponding F-code diagnostics in the installer fault table.
Who to ask for: Vaillant-trained heat pump installer/engineer (MCS-certified installer).
Certification: MCS installer certification; Vaillant product training recommended.
What you might notice
What owners and engineers report
8 owner and engineer reports mention this.
- Keeps stopping / cutting out on the aroTHERM plus (VWL ../6 A): 6 reports
- Intermittent fault on the aroTHERM plus (VWL ../6 A): 2 reports
Sources
- Heat pump control interface module (VWZ AI) operating and installation instructions ↗ · 0020291573_01 · page VWZ AI appliance interface 0020291573_01 p.32; uniTOWER VIH QW 190/6 E 0020291525_05 p.58; VWZ MEH 97/6 hydraulic station 0020291544_03 p.50; aroTHERM split hydraulic station VWL ../5 IS 0020257319_05 p.55 · Reviewed 23 September 2026
- flexoTHERM exclusive VWF 57/4 - 197/4 400V installation and maintenance instructions ↗ · 0020213394_05 · page flexoTHERM 400 V 0020213394_05 p.49; flexoTHERM 230 V 0020213395_04 p.44 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026