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toehanus 07-14-2009 10:07 AM

Faucet Leaks When Shower is On
I have a delta single control faucet shower in the bathroom. It has the plunger type diverter for the shower. Anyway, the faucet leaks when the shower is on. I replaced the diverter and the faucet still leaks when the shower is running. Any ideas on how to fix this? Thanks!

Redwood 07-14-2009 03:08 PM

As in leaks...
Do you mean it has a small stream out of the spout, large amount of water out of the spout, or, it leak back where it meets the wall?

The first would be normal as it allows the diverter to drop preventing a surprise for the next user...

majakdragon 07-16-2009 07:59 AM

Most diverters are not 'water tight". Most spouts are cast and the sealing surface is not perfectly machined to allow drip free operation.

Redwood 07-26-2009 02:03 PM


Originally Posted by majakdragon (Post 32327)
Most diverters are not 'water tight". Most spouts are cast and the sealing surface is not perfectly machined to allow drip free operation.

Yea it's actually a nice feature that the water leaks out and the diverter resets so the next person doesn't get a cold surprise.

anubis39307 08-25-2009 02:10 PM

How do you break loose the old faucet (40 to 50years old) loose in order to replace it?

Nestor_Kelebay 08-25-2009 11:06 PM


Have you replaced the tub spout in your bathroom? The reason I ask is that chinese manufacturers will make spouts that LOOK identical to the Moen or Delta spouts, but won't have the same closing action that true Moen or Delta spouts do.

For example, Moen makes a slip-on spout called the Model #3931. It has the standard plunger style gate that most diverter spouts do. The difference is that the #3931 will have something called a "cup washer" in that gate that "inflates with water" when it's pushed in front of the end of the copper pipe the spout slips onto. When that cup washer inflates, the front of it moves forward to seal against the end of the pipe so that no, nada, zero, zilch water leaks out the spout when the shower is on. Delta and Ondine have closure mechanisms that work on a pressure principle just like the water mixing valve on a washing machine, and neither should lose any water when the shower is on either.

I'm pretty sure that if you phone up some of the plumbing wholesalers in your area and find out who the Delta sales rep or agency is in your area, they'll have Delta spouts on display so that you can compare yours to. I expect yours is a cheap spout made in China that's intended to merely look the same as a real Delta diverter spout. Home centers will sell these offshore knock offs because they cost a lot less than the real thing, but they just don't work as well as the real thing.

In my case, it's important for me to have good shower performance in my bathrooms because people do want that. I have installed Niagara N2130 shower heads (which won an award for excellence in design) because they provide the best shower performance while keeping water usage low and Moen 3931 diverter spouts (which use that "cup washer" design) in all of my apartments. Since I made that switch, not a single tenant has complained about the performance of the shower in their bathroom.

Moen also makes screw on diverter spouts with the cup washer in the gate, and you can get a repair kit that includes a new cup washer, gate and plunger to rebuild your Moen diverter spout if the cup washer is ever damaged and starts leaking water. Just ask for Moen Part #10644. They're supposed to cost $12 each (almost as much as a new #3931 spout, but if you tell Moen that your spout is leaking, they'll send you a repair kit free.

The other important advantage of the Moen #3931 slip on diverter spout is that it doesn't have a set screw that impinges on the copper pipe. Instead it has a "yoke" that clamps around the pipe, thereby distributing the gripping force over a much larger area of the pipe, and therefore it's less likely to damage the copper pipe.

Nestor_Kelebay 08-25-2009 11:26 PM


If the spout is 50 years old, then it almost certainly screws on. However, there are different kinds of "screw on" bathtub spouts. Bathtub spouts that old will typically screw onto a fine threaded brass nipple that sticks out about 5 inches from the wall. And, I don't think you can get diverter spouts to replace that style of spout. Most likely, this will be the kind of tub spout you have.

The other kind of screw on spout screws onto a 1/2 inch Male Iron Pipe fitting that's close to the wall. You can buy diverter spouts for this kind of screw on spout.

Take a look on the bottom of your tub spout right close to the wall. If there is an opening there and you can see a set screw in that opening (using a mirror and flashlight) then you have a slip-on spout. Otherwise, it's a screw on spout.

dolji889850 02-15-2010 01:21 PM

The diverter is supposed to allow some bypass to relieve pressure and allow the diverter to drain back to the tub spout position. This will avoid someone turning on the faucet and getting a face full of hot or cold water

Redwood 02-15-2010 04:11 PM

I believe the original poster is referring to a valve that has the # RP5649 diverter in the valve body...

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