BoilerFaultCodesGlow-worm S.97 Fault Code
Also written as S97 — same fault.
The Glow-worm S.97 fault code means: your boiler is temporarily pausing to check the system's water pressure before it starts up to provide heating or hot water.. It appears on 22 Glow-worm models in our database.
Technical description: Water pressure sensor check is running, demand (DHW or heating) is blocked
What causes the Glow-worm S.97 fault?
This fault occurs because the boiler's internal computer needs to verify there is enough water pressure in the system before it allows the burner to fire up. It is often caused by a slow-reacting pressure sensor or a slight delay in the system reaching the required pressure threshold after a long period of inactivity. While usually a brief check, if it persists, it suggests the sensor is struggling to send an accurate reading to the main control board.
This status is more frequent in autumn when the heating is turned back on for the first time, as system pressure can settle or drop slightly during the summer months.
DIY fix possible
Wait for 30 to 60 seconds to see if the code clears automaticallyCheck that the water pressure gauge is between 1.0 and 1.5 barTop up the water pressure using the filling loop if it is below 1.0 bar
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 S.97: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Glow-worm models that show the S.97 fault code
Click a model for the full fault code list and model-specific repair notes.
- 30cxi Repair: £80-150
- 38cxi
- Betacom4 Repair: £120-250
- Easicom3 Combi
- Easicom3 System Repair: £120-250
- Energy Repair: £100-200
- Energy System Repair: £120-250
- Energy2 30c
- Energy7 Combi Repair: £150-250
- Energy7 System Repair: £120-250
- Essential Repair: £100-250
- Flexicom 18sx Repair: £120-220
- Flexicom cx Repair: £120-220
- Flexicom hx Repair: £120-220
- Flexicom sx Repair: £120-220
- Sustain 12s Repair: £90-180
- Ultimate 3 25R
- Ultimate3 Combi Repair: £120-250
- Ultimate3 System Repair: £120-250
- Ultracom 2 CXI Repair: £120-220
- Ultracom 24cx 30cx Repair: £120-220
- Ultracom cxi Repair: £120-220
Source
Glow-worm S.97 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
- Glow-worm Ultracom 2 CXI manual (PDF)
- Glow-worm Betacom4 manual (PDF)
- Glow-worm Easicom3 Combi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026