Engineer's Plumbing Blog — PTR Valve

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...