Hello Travis your review indicates that your Moen Banbury Single Handle 1-Spray Tub and Shower Faucet 1.75 GPM in Spot Resist Brushed Nickel (Valve Included) when you run water out of the tub spout you also have water coming out of the showerhead. If this is the case, it sounds like you are experiencing a condition we refer to as “stacking”. This condition can best be described, as the water leaving the tub spout is not able to get out of the spout fast enough that the water begins to back up behind the wall. The only place for the water to back up to is up the shower pipe and out the showerhead.
The following is a list of the common reasons that “stacking” occurs:
-The pipe running from the bottom of the valve body to the tub spout must be ½” copper or IPS pipe. No other type of piping should be used for this connection.
-The pipe running from the bottom of the valve body to the tub spout should only have one elbow in it.
-The valve body itself was installed upside down.
-Try removing the tub spout from the pipe it is mounted on. After removing the spout, turn on the water to see if “stacking” still occurs. Please note that the water will shoot straight out of the pipe, you will need to take precautions to prevent it from splattering all over the place when it hits the back of the shower wall.
-There must be a minimum of 46” between the handle and where the pipe for the showerhead comes through the wall.
Our specially trained Product Consultants are available via our Moen Plus Support Center for technical assistance. They are available Monday through Friday from 8:00 am – 7:00 pm Eastern Time and can be reached at 1-800-289-6636.