Vaillant Secondary Heat Exchanger 065132

The Vaillant 065132 is a secondary heat exchanger used to transfer heat from the boiler's primary circuit into the domestic hot water supply. It is a plate-type unit fitted across a number of Vaillant Ecomax and Ecotec Exclusive combi models. Its job is to raise the temperature of the incoming mains water as it passes through the boiler on a hot water demand.

• Hot water running cool or lukewarm while the heating circuit works normally
• Domestic hot water temperature fluctuating or dropping away during a draw-off
• Reduced hot water flow rate at the taps compared with previous performance
• Water weeping or staining around the plate stack or its connections
• Sludge or scale build-up restricting flow through the secondary circuit

• Check the appliance data badge and confirm the model and GC number against the fit list above
• Confirm the existing heat exchanger's plate count and physical size match the unit being removed
• Inspect the primary circuit for sludge or scale, as this is a common cause of secondary exchanger failure
• Check whether the appliance's seals and O-rings also need renewing at the same time