BoilerFaultCodesWhat the manual says
Manufacturer manualContact thermostat triggered. The surface-mounted thermostat or the condensate pump has triggered.
What causes this fault?
This fault occurs when a safety device detects that water isn't draining away correctly or the system is getting too hot. The most common reason is a blockage in the waste water pipe or a failure in the external pump that pushes excess fluid out of the boiler. To prevent internal damage or a leak, the boiler automatically shuts down as a protective measure.
This fault is significantly more common during freezing winter temperatures, as the external condensate pipe can freeze, causing water to back up into the boiler.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like S.39: no call-out fees, no surprise bills.
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Related fault codes
All 146 fault codes on the ecoTEC pro 24 VUW GB 246/5-3
Seeing a different code? Every code this model can display, in one place.