A check valve may be installed in a house water line in order to regulate water entering and exiting. Though a check valve in a water line requires little external interference, it is important to test the check valve every now and then to ensure the correct water pressure is entering the home. To test the check valve, begin by opening the high-side and low-side bypass valves. Then attach the high-side hose on the test kit to the fitting, which is usually to the left side of the check valve.
The low-side of the hose from the test kit should be attached to the testcock to the right of check valve. Turn off the first shut-off valve (connected to the water line) and then slowly open the testcocks to which the hoses are attached. Open the high-side bleed valve and then close the low-side bleed valve. Read the PSI on the test kit to see if the water pressure is where it needs to be.