RPZ Backflow Assembly
Supply
Downstream
Valves
You can also tap the shutoff and test cock handles on the drawing.
Faults
Using the test kit
Needle valves. Each valve's knob sits just right of its hose on the bottom of the kit. Drag the knob up to open, down to close (or scroll over it with a mouse). A single tap snaps it fully open or fully shut.
Hoses. Tap a hose's nut at the kit to loosen it (water and air spill out at the joint, which is how you bleed a hose) and tap again to tighten. Drag the nut off the fitting to disconnect it, or back on to connect. Drag a hose's other end onto a test cock; it goes on tight. Tap that end to loosen it at the test cock and again to tighten. With the test cock shut, a loose joint vents the hose; with it open, it bleeds the assembly down slowly.
Test kit
- High side
- Low side
- Vent side
Air in the kit makes the reading wander and bubbles out wherever water carries it to atmosphere: bleed the low side with B + vent, the high side with A + vent, and a hose by loosening its nut at the kit.
Springs
Readings
- Supply (TC #1)
- Inlet (TC #2)
- Zone (TC #3)
- Outlet (TC #4)
- System
- Check #1
- Check #2
- Relief valve