How to Replace the Pressure Relief Valve on a Ferroli Modena HE 30C (UK)
Step-by-step UK guide to replacing the 3-bar PRV on a Ferroli Modena HE 30C. Part numbers, torques, commissioning.
Ferroli
The part
Fit a new 3-bar PRV on Ferroli Modena HE 30C when water dribbles constantly from the outside discharge pipe.
Isolate safely
Drain below the PRV, unscrew the old valve and fit new PTFE tape (10 turns clockwise).
Fit and commission
On Ferroli Modena HE 30C the PRV sits on the hydraulic block — torque to 25 Nm to avoid cracking the plastic manifold.
Recommission checklist
Refill the Ferroli Modena HE 30C 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
- Why does the new one still weep?
- Almost always the expansion vessel — check pre-charge first before condemning the PRV.
- Any WRAS approval?
- Only fit WRAS-approved 3-bar PRVs to keep Ferroli Modena HE 30C within its Gas Safe commissioning envelope.
- Do I need to notify the manufacturer?
- Only if the Ferroli Modena HE 30C is in warranty — Ferroli require log of any part swap for labour claims.
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