Main Secondary Heat Exchanger Kit 5112331

The 5112331 secondary heat exchanger kit is a domestic hot water heat exchanger assembly supplied by Main for use in its HE boiler range and in selected Potterton HE appliances. It transfers heat from the primary circuit to the domestic hot water supply, so it sits at the centre of the boiler's hot water performance. The kit is supplied as a complete assembly for the models listed below.

• Hot water runs cold or fluctuates in temperature while the tap is running
• Reduced hot water flow rate compared with the appliance's normal output
• Water weeping or staining around the heat exchanger body or its connections
• Scale or debris build-up restricting flow through the domestic hot water side
• Repeated lockouts or overheat faults linked to poor heat transfer on the DHW circuit

• Confirm the appliance model and GC number against the fitment list above
• Check whether the appliance requires the complete kit or a bare exchanger before ordering
• Isolate the electrical supply and drain the appliance before any strip-down
• Inspect the primary circuit and DHW pipework for debris or scale that could affect the new part