If no gauges are available to properly measure supply pressure or volume of water at the Valve, then completely remove the entire Diaphragm Assembly and open the control stop to allow water to pass through the empty valve. Valve closes off immediately. Install inside parts kit to correct above problem and update the Flushometer Valve. The size of the orifice in the by-pass is of the utmost importance for the proper metering of water into the upper chamber of the valve. Do not enlarge or damage this orifice.
Water splashes out of fixture.
If the fixture proves to be noisy, it should be replaced by a quiet action fixture. A degree of high pressure in the piping system may be dealt with by adjustment of the control stop. Other noises, which may be created by loose pipes, lack of air chambers, inadequate pipe sizes to pressure, etc., must be taken up with the building engineer. Chattering noise in the Valve. Inside Cover has been distorted from freezing or abuse.