Differences Between 3‑Valve vs 5‑Valve Backflow Test Kits

5-Valve Backflow Test Kit

3-Valve Backflow Test Kit

Why Control Matters in RPZ Testing

Both 3‑valve and 5‑valve test kits have a 5 year limited Manufacturer’s Warranty and are widely used in Australia and New Zealand for testing RPZs, double check valves, and pressure vacuum breakers.

A 3‑valve kit provides all the essential functions required for AS/NZS 2845.3 testing.

A 5‑valve kit, however, gives the operator additional control over pressure equalisation and air removal. This extra control can make it easier to achieve stable, repeatable readings — especially during relief valve testing where small pressure changes matter.

Comparing 3‑Valve and 5‑Valve Kits

How 5‑Valve Bleed Valves Improve Air Removal

In both 3‑valve and 5‑valve kits, water enters from the bottom and air exits from the top.

The 5‑valve kit simply gives you more control:

• High‑side and low‑side bleed valves are independent and vent directly to atmosphere
• Both bleed valves can be opened together without affecting the diaphragm
• The low‑side bleed can be pulsed to help the diaphragm “pump” trapped air out faster
• No risk of over‑pressurising the gauge — the bleeds do not interconnect

5‑Valve Schematic

3‑Valve Schematic

Both 3‑valve and 5‑valve kits are reliable tools for backflow testing.

A 5‑valve kit simply provides additional control that many technicians find helpful for achieving stable readings during RPZ relief valve testing.