ONYX 200L Red Heating Vessel 1 1/2 1.5 Bar

The ONYX 200L red heating vessel is a 200 litre expansion vessel intended for sealed heating systems, where it absorbs the volume change of the system water as it heats and cools. It carries a 1 1/2 connection and a 1.5 bar pressure rating, and forms part of the ONYX expansion vessel range. The vessel is finished in red, the colour normally used to distinguish heating-side vessels from potable water units.

• Water discharging from the air valve or Schrader valve when the valve core is depressed
• System pressure rising sharply once the boiler fires and falling again as it cools
• The vessel feels heavy or full of water when tapped, indicating a failed internal diaphragm
• Frequent top-ups at the filling loop to hold pressure
• Boiler pressure relief valve discharging during normal operation

• Confirm the required vessel volume against the system water content and the manufacturer's sizing guidance
• Check the system connection size matches the 1 1/2 connection on this vessel
• Verify the vessel's pressure rating is suitable for the system's operating and cold fill pressures
• Check the available space and mounting arrangement, as a 200 litre vessel requires adequate support and clearance