Function

To prevent vacuum conditions on controlled water heater tanks, brought about by tap outlets being below the base of the heater. Also used for the elimination of back syphonage from swimming pools when fitted to the hose cock used for filling or topping up.

Applications

Typical installation for a Storage Water Heater

Typical installation for a controlled pressure Thermosyphon solar water heater

Typical installation for an exterior tap

To prevent vacuum conditions on controlled pressure water heater tanks, brought about by tap outlets being below the base of the heater. Also used for the elimination of back syphonage from swimming pools or tanks when fitted to the hose cock used for filling or topping up.

Main features

Compact Size
Simple vertical fitting
Dezincification resistant construction
Hot water resistant (90°C)

Installation

Storage Water Heater
Fit tee piece to top of water outlet line. Use only non ferrous tee piece and pipe. Fit vacuum relief valve AV50A vertically in tee piece, as in the diagram shown in APPLICATION

Solar Water Heater
Fit Tee piece on top of water outlet line. Use only non ferrous tee piece and pipe and fit above water level in tank and vertically in the tee piece, as in the diagram shown in APPLICATION

Pool of Tank Supply Tap
Fit Tee piece to water supply line behind tap. Fit AV50A vertically in tee piece, as in the diagram shown in APPLICATION

Maintenance and trouble shooting

It should be noted that water borne sediment or dirt can, in certain circumstances, prevent the internal mechanism of the AV50A from functioning properly. It is recommended that in areas where the inlet pipes can cause water borne sediment, strainers are used where necessary, and properly maintained.

Approvals

Standard Association of Australia
Complies with AS1357

Office of Water Authority Hong Kong
Ref: (5) in WWO 3321/82xxviii TJ (25)