UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Dhw Heat Exchanger on a Ferroli Modena HE 30C (UK)

Step-by-step UK guide to replacing the plate heat exchanger (PHE) on a Ferroli Modena HE 30C. Part numbers, torques, commissioning.

Ferroli

The part

Fit a new plate HEX on Ferroli Modena HE 30C when DHW runs lukewarm but CH temperatures are correct — classic scaled plate symptom.

Isolate safely

Isolate mains cold and CH, remove the four Allen bolts and lift the plate HEX from the hydraulic block on Ferroli Modena HE 30C.

Fit and commission

Fit new O-rings and grease with silicone; never re-use the old seals.

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

Descale or replace?
Descale up to 15% flow loss; replace beyond. Sentinel R200 works but takes 4 hours.
Plate count?
Ferroli Modena HE 30C uses a 10-plate or 14-plate HEX depending on rating — cross-check the model suffix.
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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