Ideal 174821 Plate Heat Exchanger Kit

The Ideal 174821 is a plate heat exchanger, also known as a secondary heat exchanger, used in Ideal domestic gas boilers. It is a compact stack of corrugated stainless steel plates that keeps the boiler's primary circuit water and the domestic hot water supply in separate channels while transferring heat between them. This is the component that heats the water leaving the hot tap, rather than the primary heat exchanger that takes heat from the burner into the system water.

• Domestic hot water runs hot and cold, or the temperature at the tap fluctuates when other outlets are used
• Reduced hot water flow rate compared with the cold supply, often caused by scale or debris blocking the plate channels
• Water weeping from the plate pack or from the seals where the exchanger joins the pipework
• Boiler locks out or reports a fault when a hot water demand is made
• Discoloured or contaminated water at the hot tap, indicating an internal breach between the two circuits

• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
• Confirm the part number 174821 and the KITHE30 marking match the component being removed.
• Check whether new gaskets, seals or connection washers are needed for the pipework joints before the boiler is reassembled.
• Have the appliance GC number and model details to hand so the correct variant is supplied.