How to Replace the Primary Heat Exchanger on a Alpha CD-32C (UK)
Step-by-step UK guide to replacing the aluminium/stainless primary HEX on a Alpha CD-32C. Part numbers, torques, commissioning.
Alpha
The part
Replace the primary heat exchanger on Alpha CD-32C when you see combustion products blowing back, F62/L9 faults or sooting on the burner.
Isolate safely
Drain and cap all four connections on Alpha CD-32C. The HEX weighs 12–18 kg — get a second pair of hands.
Fit and commission
Torque new HEX unions to the OEM figure (typically 40 Nm for cast, 28 Nm for stainless) and refit new burner and door gaskets.
Recommission checklist
Refill the Alpha CD-32C 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
- Warranty implications?
- A HEX swap on an in-warranty Alpha CD-32C must be logged with the manufacturer — otherwise the labour claim voids.
- System clean first?
- Mandatory — power-flush and fit a magnetic filter or the new HEX will block within two years.
- Do I need to notify the manufacturer?
- Only if the Alpha CD-32C is in warranty — Alpha require log of any part swap for labour claims.
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