It has to work. Then again, if you say it doesnÂt, I believe you. But my first sentence was correct, in that, such an arrangement is made to be open at two places, the spout and the showerhead.

Water naturally falls, so it will try first to exit the spout. When the diverter is actuated, and it cannot fall, it seeks the other option. This is a nice arrangement, because when the shower is shut OFF, it will drain the riser tube, so that you donÂt get a blast of chilly water next time.

There are three reasons why this might not work. The first two involve the installation. If the shower was Âabandoned by an earlier user, it may have been capped-off at the top of the mixing valve. Similarly the valves are Âdirectional. It may be in upside down.

But, often the problem is in the Âsmart valving that is used for anti-scald control. Since it is "anti-scald," these are made more cheaply by sensing too-hot water and stopping it, while the COLD still flows.

Some valves shut down both sides. If the cartridges in these are installed upside down (handle 180° out of position) no water will flow. But I donÂt think it can be true for the shower-only.

If you think the water should flow to the showerhead, it can be in the mixing valve itself. You can get a Moen repair kit almost everywhere. If you remove the cartridge, you may find that the seals have been sheared by sharp edges of the valve body, where the finely-machined bore meets the cast passages at an oblique angle.

As this material accumulates, it can lodge in the small port that feeds the riser, eventually creating a packing capable of stopping the water from rising. Before installing a new kit, insert an emery board into the valve body and try to round off any sharp edges.

If this is the problem, the port will need cleaning, too. You can probe that with a small wire (paper clip) or try blowing back an air blast thru the shower arm. Any clogging material will end up in the valve and must be washed out before reassembly. Then run the shower water with the head off for the same reason, before reinstalling it.

Pinoke

Our faucet started leaking recently out the tub spout. This morning it was still leaking but now when I turn the knob, nothing changes. Will replacing the cartridge fix this or something different needed?