Troubleshooting a Faucet Backflow Preventer

A faucet backflow preventer is essential to the avoidance of water contamination. For instance, when a hose or another device is connected to a faucet, contaminants can get into the main water supply as soon as the hose nozzle is turned off. This is due to water backflow. To prevent this from happening, a backflow preventer has to be installed. When the device fails, here are some troubleshooting tips.

The Relief Valve Releases Water On and Off

This is probably due to fluctuations in the inlet or outlet pressure. Inspect both check valves on inlet and outlet portions of the device. If the valves are faulty, replace them with spring-loaded soft-seated check valves to solve the issue. Be sure to install it as close as possible to the shut off valve if it is located on the outlet portion. Test the relief valve again.

Relief Valve Constantly Releases Water

Dirt on the check valve may be the cause of the issue. Flush the valve clean to fix it or replace the valve if this does not work. A dirty relief valve seat may also cause the problem. Inspect the valve seat, clean it and retest the valve. If the seat still causes problems, replace it with a new one.

In case the piston O-ring cannot move freely, remove it from its position, clean any dirt on its surfaces and place it back to its original position. Use some greasing material to make it free to move. Replace it if it is worn out. If the valve has not been assembled correctly, remove it from the device and re-install it properly.

In addition, check the downstream system in case of freezing or water hammering. Disassemble the unit and remove any frozen water or any clogged debris to fix the issue.

Excessive Drop in Valve Pressure

Inspect the strainer to see if it is clogged or dirty. Clean the strainer properly of any debris restricting water flow or replace it if it is damaged. Check the size of the valve as well to see if it is the recommended size for the flow. If the valve is too small, the pressure will drop significantly. Make sure that the replacement follows the recommended specifications for the required water flow.

Water Does not Flow Downstream

This has something to do with the installation of the valve. Check if it is installed facing the proper direction. It should follow the direction of the flow. If the downstream gate valve is leaking, replace it with a new one.

Valve Easily Gets Clogged and Dirty

If the valve usually gets dirty causing problems in the other areas of the device, then there must be a problem with the water filtration. Although the strainer traps any debris entering the device, the particles may be too small to be trapped in the mesh. If that is the case, remove the strainer from the assembly, purchase a new one with a new one with a finer mesh and install it. In time, the strainer may need to be removed, cleaned and reinstalled.