Fluctuating Water Pressure
Q: We have an intermittent hot water pressure problem. At times the hot water pressure will surge from full pressure to very little to no pressure. While this is happening, the plumbing in the house makes a sound kind of like emptying a large metal gas can without the air vent open. This pressure surge does not happen all the time. When it does, it usually only surges 2-4 times, then normal pressure resumes.
Lately it has gotten worse and after surging several times with increasing time between high and low, the pressure will drop to just dripping and stay there for several minutes. Opening the bathtub faucets will sometimes help. This problem was somewhat frequent during winter over a year ago, but did not happen at all for the last 8 months. It is getting to the point now where it is happening almost all the time. Any clues?
A: Does this happen at various times at every faucet in the house or at only some of them or one of them? Do you have copper piping in your house or steel? Are the nipples on the water heater brass or steel? And what kind of faucet controls do you have? Are they dual or a single control for both hot and cold? -- Larry
Q1: Thank you for your reply. This is happens at any faucet, tub, even the washer and dishwasher. The piping is copper. The connections to the water heater are threaded, silver in color, but not rusted. I have both types of faucets (both types will exhibit the problem).
A1: Hello: May I suggest you get a pressure gauge at the hardware store? Put it on the drain of the water heater and leave it there (with valve open). When pressure fluctuates next time, have a look at the gauge. If it drops, you know the problem is in the cold supply. If it remains at its normal pressure, the problem is downstream of the heater. It's a start. Once you know that, knowing where to look will be easier. -- Larry (5/24/05)
Q: I have a gas hot water heater (Bradford White - 1996). There's a couple problems that just started, and I'm thinking all related. The burner turns on, and seems to have a normal flame, but the water doesn't heat up. When I open the pressure release valve at the top of the tank, cold water comes out. Also, at the faucets around the house there's very little hot water pressure and the water is cold. The cold water pressure is fine.
About a week ago, the pressure valve blew for the first time I've seen. (We've had the house about 6 months). At the time, I released the pressure a few times, and things went back to normal. I drained and flushed the tank, but nothing changed. There is still just a trickle of water out of the hot water faucets and it's cold. The house was built in 72, and has galvanized pipes - if that makes a difference. Any ideas about what the problem is? Do I need a new tank, or is this something minor to fix?
A: You need to start with a pressure guage. Get one that reads around 0 to 200 psi and has the sort of threads that can screw onto a hose bibb. Put it on the water heater's drain. Jot down the static pressure; that's when no water is being used. Turn on two or three cold taps and note the pressure. If it falls a lot, the supply pipe to the house could be getting clogged up. Now close the cold taps and open one hot tap. Does the pressure fall? If it falls a lot, the supply to the heater is clogged. If it didn't fall at all, open up two more hot taps. If the pressure doesn't fall, you know the outlet of the heater is clogged. The neat thing about a gauge is it eliminates a lot of guesswork. Once we know roughly where the clog is, a plan can be made for fixing it. Let us know what you find... and happy holidays. -- Larry
Q1: Oops - not the water heater at all. The reason for low pressure and no hot water was that the hot water pipe was busted underneath the house. Completely filled my crawlspace with a couple thousand gallons of water. I'm wishing it was just the water heater.... (12/25/07)
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