Leaking Tub Spout with shower engaged

[lbaccar23]

I have water that streams out the tub spout when the shower is engaged. My diverter valve is the type that looks like the hot and cold valve but is in the middle of those two.

What can the problem be? and can this be corrected with the water supply still on? The problem is that I live in a high rise condo and the water supply is only shut down on certain days.

Thansk,

Larry

[LazyPup]

Most three knob shower mixers with a center diverter use the common stem washers.

The two outside faucetts (Hot and Cold) regulate the flow of water but the center stem is made slightly different. When the center stem is open the water is free to follow the path of least resistance and flow through the stem and down to the spout. When the stem is closed the passage to the tub spout is closed and the water is forced to rise up the riser to the shower head.

There is a common seat and rubber Bibb washer on the inner end of the stem that closes the water off to the spout.

Providing you are careful to insure that both the Hot and Cold faucetts remain closed you can service the "diverter stem" without turn the system water pressure off.

Begin by turning the diverter stem all the way open, then remove the handle and trim escutcheon.

Once you have the trim escutcheon removed you will see the diverter stem. Generally only the end of the stem shaft is protruding through the wall so you will most likely need a plumbers socket to unscrew the diverter stem from the mixer body. (You can buy a set of plumbers sockets at any local hardware store for about $10).

When you examine the diverter stem you will see a nut on the exterior end when the handle shaft enters the diverter stem body. That is a packing nut that compresses a fiber packing against the faucett handle stem to prevent it from leaking. Do not remove that nut. If you look inside the hole in your wall you willl see where the diverter stem base meets the mixer body and you will see another set of nut flats molded on that stem to permit removal. Select the proper socket that fits the inner nut flats and unscrew the diverter assembly then pull it out. On the inner end of the diverter you will see a rubber bibb washer that is held in place by a machine screw. Remove the screw and pry the old washer out, then insert a replacement washer and tighten the screw back in.

While you have the diverter stem out reach your finger into the hole in the mixer body and feel the seat where the bibb washer seals. If you feel and chips, cracks or mineral scale buildup I would highly recommend replacing the seat as well.

To replace the seat you will need a faucett seat wrench. (You can get an inexpensive seat wrench at your local hardware for about $6). Insert the seat when into the center of the seat. The seat has mating flats molded on the interior so the seat wrench can turn it. Unscrew the seat and once its loose try to balance it on the tip or your seat wrench as you carefully pull it out. Take the seat to your local hardware store and they can match you up with a new one. Here is a tip. Faucett seats are made in Brass, Monel Metal and Stainless steel. The brass or money metal type are only about $3 to $4 while the stainless steel one may be $6 to $10 however a stainless steel seat will last a lifetime which the brass or monel metal may only last a couple years, in the long run the stainless steel seat is a bargan.

To install the new seat slip it snug on the end of your seat wrench and use the wrench to reach it into place. (I usually apply a couple wraps of teflon on the seat mounting threads before installing it).

I am attaching an simple illustration that may help you see the internal layout.



Check your diverter stem. Most of them have a small fiber flat washer seal around the mount threads which seals the diverter to the mixer body. If there is no fiber seal present you may need to get one.