How to Replace the Pressure Sensor on a Worcester Bosch Greenstar 28i (UK)
Step-by-step UK guide to replacing the hydraulic pressure transducer on a Worcester Bosch Greenstar 28i. Part numbers, torques, commissioning.
Worcester Bosch
The part
Fit a new pressure transducer on Worcester Bosch Greenstar 28i when the display shows correct pressure at rest but locks out on heat-up.
Isolate safely
The transducer on Worcester Bosch Greenstar 28i threads or clips into the hydraulic block. Drop pressure to zero before removal.
Fit and commission
Refit with a new O-ring; over-tightening cracks the plastic body.
Recommission checklist
Refill the Worcester Bosch Greenstar 28i to 1.2 bar cold. Bleed high-point radiators and the internal AAV.
Run a full flue-gas analysis after 15 minutes. Log the reading against the OEM commissioning envelope in the Benchmark book.
Frequently asked questions
- Digital or analogue?
- Worcester Bosch Greenstar 28i runs a 5 V ratiometric transducer — the display board reads voltage directly.
- Calibration?
- None — the PCB self-references at 0 bar and 1.5 bar; recommission per OEM sheet.
- Do I need to notify the manufacturer?
- Only if the Worcester Bosch Greenstar 28i is in warranty — Worcester Bosch require log of any part swap for labour claims.
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