VOKERA7204 8 Litre Zilmet Expansion Vessel

The Vokera 7204 is an expansion vessel used in Vokera Eclipse and Excel boilers. It is a sealed steel vessel with an internal diaphragm that separates a pre-charged air cushion from the system water. As the heating water heats and expands, the diaphragm flexes to absorb the extra volume, keeping the sealed system pressure within its working range and protecting components such as the pressure relief valve from unnecessary discharge.

• System pressure falls repeatedly and the filling loop has to be used to top up
• The boiler locks out or displays a low pressure fault shortly after refilling
• Water discharges from the pressure relief valve during normal heating cycles
• The pressure gauge climbs sharply as the system warms up
• Water, staining or corrosion is visible around the vessel connection or its air valve

• Check the boiler model and GC number on the appliance data badge against the part number
• Confirm the vessel currently fitted is marked 7204 before ordering a replacement
• Check whether the connection seal or washer needs renewing at the same time