Moved house recently, new place has had bad water hammer if any tap/shower turned off too quick. Checked toby this morning, found it not fully on. Turned it fully on, and water hammer has stopped which seems a bit odd. Water pressure is about 80psi I understand that toby not turned fully on would reduce flow and may seem to have lowered the pressure but in reality the pressure is unchanged,, just reduced flow. Why would the water hammer have stopped though?
peanuts37,
Dec 24, 5:35am
Because pressure in pipe with tap turned on would be much less with toby not fully on. Might go from 10psi to 80psi when turning tap off instead of maintaining say 40psi with tap on to 80psi. Much less pressure difference.
muzz67,
Dec 24, 5:45am
Righto,, difference. Makes sense, cheers.
saki,
Dec 24, 6:28am
you can get specific washer kits for the tap(s) the cause the W/H from M10
msigg,
Dec 24, 6:31am
Well maybe you get more eddies with the valve half off, as for pressure it will be similar but flow rate will be down. Anyway you sorted this. Now more posyer will come up with some different ideas.
mechnificent,
Dec 24, 11:37am
Crikey 80 lb. my gravity system works at about 4lb. haha. Life in the country.
mechnificent,
Dec 24, 11:38am
Then. my electricity is only 12 volts too. sigh.
s_nz,
Dec 24, 12:37pm
Dabbled in a bit of transient analysis at work for big piping systems using computer modeling.
Basically pressure waves bounce around the system after a disturbance, and you tweak the design (i.e. put slow closing valves, flywheel between pump and motor, air chamber etc to keep transient pressures below allowable limits.
One system we did, we had a little (25mm I think) valve which opened and dumped water for 30sec or so while the main valve was closing. Never got to see it run in person, but the system was under really high pressure, so apparently it was really dramatic the water blasting out of this valve, across the length of a shipping container.
I would guess that pressure waves were bouncing back off the partially closed Toby.
But as another person said, it could be the much higher pressure change in the system.
I don't think that throttling with the Toby by the previous occupant was a great idea. If pressure is too high, a Pressure regulating valve is the way to deal with it.
Not quite sure what the max pressure NZ domestic pipework is rated to, but 80psi is getting fairly high.
intrade,
Dec 25, 2:30am
Thats interesting. Because i never could find a defined reason for water hammer. i got it if i snap shut the European taps and my flow will be reduced thru 2 water filters and pressure from electric pump tank water.
trade4us2,
Dec 25, 3:59am
Since my house is at sea level the water pressure is very high, like 100 psi or higher. I had problems with all taps, and water hammer and screeching noises when taps were turned on. I put a pressure reducing valve in the pipe to the house and that fixed the problem. I have one outside tap at high pressure and still have problems with that leaking.
tweake,
Oct 6, 2:53am
most of the pipe work is ok. but local plumber did express some concern with older pipes and our town water pressure being so high.
i got a pressure regulator fitted a little while ago to drop the pressure, mostly to help match up with the low pressure hot water system (it has booster pump). i think the high water pressure was playing havoc with the hot water pressure regulator and causing it to vibrate at certain flows. certainly the drop in cold water pressure has made the taps a lot better to use.
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