View Full Version : Strange change in shower/tub water pressure

08-13-2008, 02:21 PM
Hi. A few weeks ago we had the seats and stems replaced on our hot, cold, and diverter.

Immediately after this was done (and never before) the water pressure started changing on us several seconds after we turn the water on. It's only on the hot side.

Basically, when you turn on the hot water it comes out at a "normal" rate at first. After about 10-20 seconds the water pressure cuts down almost in half. I then have to turn the knob again to increase the water, the water pressure goes back up to normal and remains normal for as long as I leave it running.

The plumber we used for the job says that this can't be related to the job he did. But it never happened before we had the job done, so I'd be surprised if it was just a coincidence.

Can anyone explain to me what might be happening so I can get the plumber back out to fix this problem? Thanks.

08-13-2008, 04:41 PM
It is possible that the plumber used the wrong washer, their are flat washers and cone washers he may have used the wrong washer for the handle. There is no way here we can tell which washer it should be. It is also possible the washer is loose. But, I am not sure if that would cause your problem.

08-13-2008, 06:42 PM
The packing may be too tight and is turning the stem back...
Are the handles hard to turn?

08-14-2008, 05:50 AM
Yes - I thought the handles would "turn like new" - but they are hard to turn and have not loosened up after about 3 weeks of use by 2 people. They also screech and do not turn smoothly - sometimes they seem to turn with zero resistence while turning on or off - but to begin turning them on or to turn them all the way off, I really have to crank hard on the handles.

08-14-2008, 05:50 PM
You need a better plumber!
On the stem there is a packing that squeezes against the stem and prevents water from leaking out. This is adjusted by the packing nut.


Some plumbers believe that this nut should be cranked down gorrilla style to prevent leaks. Nothing could be further from the truth. I like to make sure that the stem is well lubricated and the packing is only tight enough to stop the water from leaking past the packing. When the packing is too tight the wear of the packing is accelerated and the handles become hard to turn. This makes it so that it is impossible to feel when the washer contacts the seat. This leads to overtightening and accelerated wear of the washer, and possible breakage of the handles.

08-18-2008, 06:27 PM
Hi. Thanks for the responses so far. Just wanted to update on the result when the plumber came back.

Supposedly the problem was that scaling got stuck in the shutoff valves when the work was done, so the valves were flushed and a bunch of stuff came out and now the pressure is fine.

As far as the knobs themselves, supposedly these washers don't turn smooth b/c this is a really old building and the plumbing does not take ceramic washers, which turn more smoothly - or at least this is what we were told. He greased the packing nut with silicon grease and now the knobs turn much much more easily and I don't have to crank it all the way until the know won't turn at all anymore to get the water to turn off.

SO, it's apparently fixed now, but just wondering if these methods and this information sounds right. Thanks.

08-18-2008, 06:40 PM
Sounds like he fixed it the second time!
I'd rather fix it the first time myself!:cool:

08-19-2008, 06:17 AM
The age of the building does not determine whether you can change to ceramic seal stems. It is the make and model of the faucets themselves. Usually your problem is caused by something expanding when it gets hot. "scale" in the piping is as good an excuse as anything as long as he also fixed the real problem.

08-19-2008, 06:23 AM
I suspect adequate lubrication and proper adjustment of the packing had a lot more to do with it...:cool: