How to Replace a Worcester Bosch Greenstar 25i Pressure Relief Valve (UK)
Fit a new pressure relief valve on the Worcester Bosch Greenstar 25i. UK part number, isolation and torque steps.
Part number
The Worcester Bosch Greenstar 25i uses the 3 bar PRV 87161424690. Check the GC serial number sticker inside the case — Worcester Bosch revised the pressure relief valve at least once during production.
Isolate
Turn off the gas at the isolation cock. Switch off 230 V at the fused spur. Drain to just below the pressure relief valve: on the Worcester Bosch Greenstar 25i, the drain-off is on the return pipe.
Fit
Unclip the pressure relief valve. Transfer the O-rings if OEM includes new ones — always fit the new seals supplied. Torque any brass unions to 25 Nm. Refill to 1.2 bar, bleed and fire for a wet check.
Frequently asked questions
- OEM or compatible?
- For gas-carrying components on the Worcester Bosch Greenstar 25i always fit OEM. Non-gas parts (fans, PCBs, pumps) — OEM keeps the warranty valid.
- Do I need to re-commission?
- Yes — record combustion CO/CO₂ ratio after any gas-side work per BS 6798.
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