BoilerFaultCodesVokera E04 Fault Code
The Vokera E04 fault code means: your boiler has lost the connection to the temperature sensor responsible for your hot water storage tank, meaning it cannot accurately monitor your hot water temperature.. It appears on 2 Vokera models in our database.
Technical description: NTC3 OPEN Storage heater probe not connected
What causes the Vokera E04 fault?
This fault occurs when the boiler's control system fails to detect a steady flame after several attempts to light. The most common reasons are a buildup of carbon on the ignition parts, an inconsistent fuel supply, or a sensor that has become too dirty to 'see' the flame. It functions as a safety shutdown to ensure gas does not flow without being safely burned.
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 →Avoid the next call-out bill
A cover plan would handle faults like E04: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Vokera models that show the E04 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera E04 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026