Vacuum Relief Valve

For Hot Water Storage Buffer system

Vacuum relief valves are used in water tank applications to automatically allow air to enter into the piping system to prevent vacuum conditions that could siphon the water from the system and damage/ Collapse water tank equipment.


  • Low profile
  • All brass body
  • Protective cap
  • Vacuum: ≤—0.0034Mpa.
  • Venting Capacity: 1.55L/s
  • Maximum working pressure: 1.38MPa.
  • Maximum temperature: 110℃
  • Vacuum Relief Valve Sizes: 1⁄2″ Male NPT

Operating Principle

The valve opens the outlet on reaching the settings for:

– temperature: the thermostat compound inside the temperature sensor 1) submerged in the hot water storage heater, expands as the temperature increases. This expansion causes a thrust pin to move and act on the obturator 2) opening the valve. The valve is set to open at temperatures of over 90°C.

– pressure: the obturator, opposed by a set spring, raises on reaching the pressure setting and opens the outlet completely. The pressure setting is chosen according to the maximum permissible pressure in the system.

As the temperature and pressure decrease, the opposite action occurs with the valve subsequently reclosing within the set tolerances.

MODEL Size Connection A B Weight
in in mm mm (g)
VZA 15 1/2 1/2 50 50 101


ZA-15 Vacuum Relief Valve should be installed at the highest point of the cold water inlet, ZA-15 must be mounted vertically, as shown in position, between the vacuum valve and the tank, no need to install additional valve. Installation location must be typical and correct, otherwise it will be case the valves does not work, or even Damage!

This website uses cookies and asks your personal data to enhance your browsing experience.