Law Supply, Inc.
Web Page - Expansion Tanks

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Installation Requirements
1.	A pressure reducing valve with bypass, must be installed between the cold water inlet shut off valve and the expansion tank.  The valve must be adjusted to provide cold water line pressure of 40 PSI.
2.	To properly adjust and provide for periodic maintenance of the pressure reducing valve, a pressure gauge may be installed between the pressure reducing valve and expansion tank.
3.	The entire piping system, including the pressure reducing valve and gauge , must be protected against below freezing temperatures.
4.	The expansion tank must be installed no closer than 18" to the water heater cold water inlet.
5.	The expansion tank is designed to be supported by the system piping in a vertical position and this is the recommended position.
6.	If the expansion tank must be installed horizontally, it must be supported by adequate strapping.

Expansion Tank Air Charge
The expansion tank should have a 40 PSI air charge.  To check the air charges:
1.	Shut off main cold water supply.
2.	Open a water faucet and allow to run until the water stops running.
3.	Use a tire gauge to check the tank's pre-charged pressure.  If adjustment is needed, only a manual type tire pump should be used.
4.	Open the cold water inlet valve.  Open a faucet and wait until a steady stream of water is flowing.  Then, shut off the faucet.