BoilerFaultCodesVaillant S.22 Fault Code
Also written as S22 — same fault.
The Vaillant S.22 fault code means: your boiler has detected that hot water is being called for, but it believes the pump is running when it shouldn't be or there is a circulation issue preventing proper operation.. It appears on 26 Vaillant models in our database.
Technical description: DHW demand – error pump running
What causes the Vaillant S.22 fault?
This fault occurs when the boiler detects a conflict in the heating water flow while trying to provide hot water. It usually means the internal pump is stuck in the ‘on’ position or a sensor is sending incorrect signals to the main control board about water movement. This prevents the boiler from safely managing the temperature, leading to a shutdown to protect internal components.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Vaillant models that show the S.22 fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax Repair: £180-350
- Combi Compact 242EB Repair: £180-350
- Combi Compact 282EB Repair: £180-350
- ecoTEC
- ecoTEC 65kW Repair: £180-450
- ecoTEC exclusive
- ecoTEC plus
- ecoTEC Plus 615
- ecoTEC Plus 620
- ecoTEC Plus 625
- ecoTEC Plus 630
- ecoTEC Plus 635
- ecoTEC Plus 65
- ecoTEC Plus 832
- ecoTEC Plus 836
- ecoTEC Plus 840
- ecoTEC Plus 938
- ecoTEC plus Regular
- ecoTEC plus System
- ecoTEC Pro
- ecoTEC Pro / ecoTEC Plus Repair: £180-450
- ecoTEC Pro 24
- ecoTEC Pro 28
- ecoTEC Pro 30
- ecoTEC sustain
- Home System
Source
Vaillant S.22 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026