Engineer's Plumbing Blog

The PTR pressure temperature relief valve regulates the pressure caused by water volume expansions during normal heating cycles in a hot water service. The PTR valve relieves this increase in pressure by a controlled water dripping into a drain line typically of 2 to 5 litres per day depending on the hot water usage.  The PTR pressure temperature relief valve also acts as a mechanical protection device for the hot water services. In rare occasions of a faulty thermostat or heating element, the hot water service can overheat, building a dangerously high pressure and temperature inside. When this pressure or temperature exceeds the PTR valve's rating, it will...

Hose taps are attached to sides of homes and commercial buildings. The hose tap outlets have standard BSP threads that can connect to garden hoses, vacuum breakers and other threaded accessories when in use. The hose tap sizing is classified based on the water inlet (the side that screws into the wall) BSP thread size in either 15mm (1/2") or 20mm (3/4"). In plumbing terminology and trade references, they are commonly refereed to as 15mm and 20mm taps. The hose tap outlet thread is always one size larger than the inlet thread size. A 15mm tap will have a 15mm...

Reduced Pressure Zone RPZ valves are backflow preventer devices to protect portable drinking water in the mains supply from contamination in applications such as industrial processes, restaurants, swimming pools and irrigation. Compared to a DCV, the RPZ features an additional differential release valve in the center of the valve body. In cases of a check valve mechanical failure or debris caught inside, the differential release valve opens to cut off the contaminated water source to the portable water mains supply.  The RPZ employs two in-line, independent check valves, captured springs and replaceable check seats with an intermediate relief valve. These features...

Double check valve DCV backflow preventers are designed to protect portable drinking water in the mains supplies from cross-connections in low risk water applications only, where no hazardous chemicals are present. A RPZ reduced pressure zone valve backflow preventer must be used instead in all other situations, when a DCV is regarded as insufficient protections by plumbing authorities. The RPZ design differs from a DCV by featuring an additional differential release valve as a mechanical fail-safe device. The differential release valve opens and dumps contaminated water to isolate from the mains water supply, if one or two of the check...