Plumbing issue - pulsing water supply, only at kitchen sink

Factual Questions
1

I have a minor issue with the plumbing in my home which has never been more than an amusing sound effect, but the other day moved up a notch to minor nuisance.

Let me state first that this problem occurs, as far as I can tell:

[ul][li]for hot water only (which I didn’t even realize until the dishwasher incident below)[/li][li]only at the kitchen sink[/li][li]intermittently[/ul][/li]
Sometimes when I turn on the water (via a single lever-handle ceramic cartridge faucet), it will briefly pulse a few times (how many times varies, one to four is common), and then operate normally.

Sometimes, it comes on at a severely reduced flow and I will have to turn it back off and on again for it to operate normally.

Sometimes, it starts, drops to a trickle, then comes back on without making the pulsing sound.

And then one night last week, it didn’t come on at all to speak of (imagine turning on a faucet whose shut-off valve was, well, shut off). Which didn’t really upset me, I just figured it would sort itself out. But next morning, when I discovered that the water had also not supplied the dishwasher when called for in the middle of the night, I was kinda peeved.

I tried the faucet, but there was still no flow there either, so realizing it had not sorted itself out, I did the only thing I could think of to troubleshoot something that only affected the two hot-water fed devices in the kitchen and reached under the cabinet and turned the hot water shut-off valve all the way to off, then all the way back on. Then everything was normal again.

Googling up ideas has led me to be sure that I mention the following additional items:

[ul][li]I am on city water, not a well[/li][li]I recently replaced my water heater, which neither improved nor worsened the problem (aside from the fact that I’ve never had it completely fail to come on before)[/ul][/li]
Thoughts?

2

[QUOTE=
Thoughts?[/QUOTE]

The shut off valve in the wall needs to be replaced.

3

So the hot water feed to the dishwasher comes off of a T-fitting from your sink line?

And this happens all year round, regardless of weather or outside temperature?

Does your home have exposed water lines (like in the ceiling of an unfinished basement), or are they in a poured foundation?

4

That was sort of where my thoughts were going, as well.

Of some sort, yes. I haven’t looked closely at it, but there is one shut-off valve, then both fixtures are downstream from there.

Yup.

The closest thing to exposed water lines are in the enclosed but unconditioned space of my outside storage room, where the water heater is. Less than three feet of pipe total, from wall to heater and back into the wall.

5

Sounds like “water hammer” to me (you can google that for more info).

Was this originally a well system? The reason I’m asking is I’m wondering if there is an air chamber in the system to help regulate the water pressure. If so, the air chamber might be clogged up.

The old water heater may have been releasing flakes of corrosion into the system, which could explain the clogging.

If there isn’t an air chamber in the system, then maybe air has gotten into the system at some point and it’s acting like an air chamber. Are there any faucets that are rarely used? You might want to turn them on to see if any air comes out of them.

Other than that, googling water hammer might give you some other ideas. A master plumber I ain’t, not by a long shot.

6

This was my thought as soon as I read the title. The valve needs to be replaced or at least rebuilt. I’m going to guess it’s not the quarter turn type but the kind where you screw it down (multi turn?) I’m willing to bet the washer has come off the stem and is flapping around between the stem and the seat. Sometimes it’s in the way, sometimes it’s not.

7

Those one-handled faucets brag about being “washerless,” but they have something inside that functions like a washer (usually a ball of some sort). That not-a-washer gizmo WEARS OUT and will need replacement.
~VOW

8

But the typical symptom of that is a dripping faucet*, not one that won’t come on.

The OP’s problem sounds more like a clog/worn shut-off valve or air in the water lines, as others have mentioned.

  • Yeah, just like with the old washer faucets. And it’s more expensive to repair these ‘washerless’ faucets that it was to just replace the washer! But they do seem to last quite a bit longer between replacements.
9

This has been great info, everyone. I’m now making plans to replace the shut-off valves under my sink. I haven’t decided yet if I’m up to learn soldering just yet, but it’s something I’m considering.

10

Modern plumbers actually don’t do much soldering. Now they generally use plastic pipe (cemented) or Pex (using a special crimping tool). Only copper pipe is actually soldered, and that’s not used much anymore because it costs so much.

So you may find it easier to just put a converter fitting on the end of your old pipe and replace it from there to the sink with newer style of pipe. Then no soldering involved.

11

If I’m reading this right, the issue is only on the hot water side, so the kitchen faucet and theoretically the DW have full supply of cold. The sputtering issue would be the same for hot and cold and it looks like it was doing it before you changed the hot water heater. If you’re on city water, you probably don’t have a pressure tank to get waterlogged. If it were me, I’d close the H and C feeds, take the cartridge and spout screen off the faucet, open the feeds A LITTLE and let the junk come out of the pipes/faucet from the new water heater install, clean the cartridge and reinstall and then open and close the feeds several times to get all the junk out of them and then put the spout screen/aerator back on. If it still does it, I’d replace the feed faucets.

12

If you have copper pipes I would leave the soddering to someone with experience. They do make shut off valves with ferrel fittings.