Thermal Expansion: What you need to know
If you install or have installed a backflow prevention assembly on your water service line, you need to understand thermal expansion. Here is some helpful information:
· The backflow assembly will prevent any non-drinkable water source within your residence from entering and contaminating the Oregon Water Wonderland drinking water supply.
· Water heaters are installed with a temperature and pressure valve (T&P) which is designed to relieve excessive water temperature or pressure. Also aiding in the control of excessive heat and pressure is a condition known as thermal expansion which allows extremely hot water in your hot water heater to backflow into the water main lines, mixing with the cold water and dissipating the heat.
· When a backflow assembly is installed on a household water service line, the water cannot flow back out into the water main line. This leaves the T&P valve on your hot water heater as the only release point for the overheated water.
· If the thermostat in a hot water heater becomes defective and allows the water temperature to increase to more than 212° F, and the T&P valve fails, your domestic water can allow scalding steam to be released from faucets upon personal use. This condition is rare, because the hot water heater thermostat and the T&P valve must both malfunction simultaneously. However, with a backflow assembly in place, the potential hazard exists.
As always, please call our office if you would like any more information. 541-593-2902