BoilerFaultCodesGlow-worm S.76 Fault Code
Also written as S76 — same fault.
The Glow-worm S.76 fault code means: your boiler has temporarily paused operation because it is waiting for a clear reading from the internal water pressure sensor.. It appears on 12 Glow-worm models in our database.
Technical description: Waiting period – pressure sensor
What causes the Glow-worm S.76 fault?
This fault occurs when the boiler is unable to get a steady reading from the internal pressure sensor, often because the water pressure is fluctuating or at the very limit of its operating range. The most common reason is a slow leak in the system or air trapped near the sensor, which prevents the unit from confirming it is safe to fire up. In some cases, the sensor itself may be blocked with debris or failing, leading to inconsistent data being sent to the main control board.
DIY fix possible
Check the digital display or manual pressure gauge to see if the water pressure is between 1.0 and 1.5 bar.If the pressure is too low, use the filling loop to carefully top up the system water.Restart the boiler to see if the status code clears.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Glow-worm models that show the S.76 fault code
Click a model for the full fault code list and model-specific repair notes.
- Flexicom 18sx Repair: £0-120
- Flexicom cx Repair: £90-180
- Flexicom hx Repair: £0-120
- Flexicom sx Repair: £0-120
- Ultracom 2 CXI Repair: £120-200
- Ultracom 2 HXI Repair: £120-200
- Ultracom 2 SXI Repair: £0-120
- Ultracom 24cx 30cx Repair: £120-200
- Ultracom 35 Store Repair: £120-200
- Ultracom cxi Repair: £120-200
- Ultracom hxi Repair: £120-200
- Ultracom sxi Repair: £0-120
Source
Glow-worm S.76 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026