Expansion tanks are installed to relieve the pressure that expanding hot water produces on the entire boiling system. These tanks come in a variety of sizes to suit all boilers. You must first know your hot water heater’s capacity in gallons as well as your house piping system’s water pressure before purchasing an expansion tank. Small expansion tanks can be hung vertically or horizontally if well supported. Larger expansion tanks are usually installed on the floor.
- For plumbing systems, expansion tanks must be connected to a cold water source in-between the back-flow preventer and the water heater. All expansion tanks should have their air-intake valves easily available.
- This is essential in the situation where you need to add air to the tank. In an open system, small expansion tanks should be placed high enough above the heat source that pressure from the hot water will force its way up the pipe and into the expansion tank.
- When water cools, gravity will force the water to easily flow back down into the water heater tank. In a closed system, small expansion tanks can be placed near the level of the boiler.
- Pressure within the system will force water to move from the boiler to the expansion tank and vice versa.