TROUBLESHOOTING YOUR REVERSE OSMOSIS SYSTEM
PROBLEM: WHEN WATER IS BEING PRODUCED, I HEAR A HUMMING NOISE.
ANSWER: This is a rare problem, but it does happen. There is a check valve in the plastic elbow attached to the membrane where the pure water exits. Sometimes a defective check valve produces this noise. Let us know, and we will send you a new one. When you receive it, turn off the water and close the tank valve. Unscrew the white plastic elbow which protrudes from the bottom left-hand side of the membrane housing. You will see the check valve inserted into it. Remove it and replace it with the new one. Put some teflon tape on the threads and screw it back it. Then turn the water back on and open the tank valve.
If that doesn't solve the problem, it is probably caused by the automatic shutoff valve (ASO). Let us know, and we will send you a new one. When you receive it, turn off the water and close the tank valve. Disconnect the old ASO (remembering how it was connected). Then insert the new ASO and reconnect it. Then turn the water back on and open the tank valve.