What the manual says
Manufacturer manualwater transducer - check system water pressure (temporary) / WATER TRANSDUCER LOAD THE SYSTEM
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 E041: no call-out fees, no surprise bills.
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Related fault codes
All 53 fault codes on the Unica MAX System
Seeing a different code? Every code this model can display, in one place.
Related guides you might find useful
What pressure should my boiler be?
1 to 1.5 bar when cold on most UK boilers, from the manuals.
Read →Hot water works but heating does not
On a combi it is usually the diverter valve. On a system boiler, the motorised valve.
Read →Boiler keeps losing pressure
Six most common causes of dropping pressure.
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