Quiet Banging Pipes and Balance Faucet Water Pressure
LESLIE: Brandon in California has been taking some cold showers. Well, not intentionally, anyway. How can we help you with that?
BRANDON: My old water valve, when I – it just happens just to the cold water. If I turn on the hot water, it doesn’t have the problem. But when I turn on the cold, it does this knocking or like a bang in the wall. And the pressure is reduced significantly. And it just will – it’ll come out really low pressure unless I really turn it on. And then the pressure comes back but I don’t know what – I don’t know if that’s called “knocking” or “hammer-knocking” or something like that but …
TOM: Yeah, it’s called “water hammer.”
BRANDON: Water hammer. Is that what that is?
BRANDON: OK. It’s not like a continual knocking, though.
TOM: OK. So, first of all, when you open up the faucet and all the water kind of runs forward towards it, that has a lot of force with it and that will bang the pipes sometimes. And if the pipe – especially if it’s not attached well to the floor joist or whatever it happens to go through, makes that banging sound. That’s why we call it “water hammer.” It can be lessened or completely repaired if you install a water hammer arrestor. But it may or may not be worth it, because it doesn’t really damage the pipe; it’s really just more of an annoyance.
Now, in terms of the pressure issue – so the water comes on fast and then trickles out after that? Is that what’s going on?
BRANDON: Well, it comes out normal but then it just seems like someone’s in the wall kinking the line. And it’s just coming out – like it comes out still; it’s not like trickling out, like drips.
TOM: Is it one faucet in the shower? What about the sink that’s right next to it?
BRANDON: No, there’s the three. One on the left is the hot, the center transitions it from the bathtub to the showerhead and the one on the right is the cold water.
TOM: What about your sink? Does it do the same thing at the sink?
BRANDON: No, it’s just in the shower.
TOM: So, what I would do is I would install a pressure-balance valve in the shower. The pressure-balance valve, essentially – and it’s not going to address the water hammering but what it’ll do is it’ll keep the pressure even between hot and cold – keep the mix even between hot and cold so that you don’t get any sort of shell shock when you step in the shower and somebody runs a fixture somewhere else and it changes the temperature.
LESLIE: Yeah. So no more pranksters flushing the toilet and getting a super-scalding shower.
TOM: And the fact this is only happening at the shower means it’s a problem with the valves; it’s not a problem with the plumbing lines. Otherwise, it would be happening at the sink, as well.
BRANDON: OK. That kind of makes sense. Because sometimes it’s just – sometimes it’s hard to balance when we’re in the shower. It’s like, “Oh, man, this is just scalding hot.”
BRANDON: And we’ve really got to crank up that cold to get it kind of balanced out right.
TOM: Yep. That’s what you need: a pressure-balance valve.
BRANDON: Alright. Perfect.