Child Item

How far do I turn water pressure at main?

Hello,

I’ve had a water hammer issue and washers replaced. The issue only occurs when turning the taps on, not turning them off.

I found some solutions online for air pockets and water hammering which I’ve completed.

I have turned the main back on - (maybe a silly question) how far do I turn it? All the way, half way?
as I’m adjusting the circular handle, can I leave a tap on to see how much pressure it will bring?

I have tuned it anti clockwise 6x around but it can go a lot more.

thank you for any advice.

Find more posts tagged with

Plumbing

Accepted answers

All comments

EricL

Hello @Newgreenthumb

Thank you for sharing your question about how much to turn the mains tap on. A good way to measure if enough pressure is flowing in the house is with your shower. If the hot and cold water pressure is good, a single full turn on the shower tap is often enough. But if you find that you seem to be turning the cold shower tap more often, odds are there's not enough pressure.

You'll notice this pattern with the rest of your taps in the house. The laundry taps seem to have a slow flow. Your garden tap is not delivering its usually far throw. A single turn adjustment at the mains should increase the pressure. Just keep in mind that the opposite could happen and that is a half turn on the cold tap delivers a deluge. A sure sign that the mains have been turned on too far.

You're aiming for a happy balance one where there is enough pressure to serve all your needs. In this way, you won't be too shocked when you see your water bill.

If you need further assistance, please let us know.

Eric

Newgreenthumb

@EricL

thank you very much for this.

my shower hot top seemed to turn a few times with the cold being more then enough. Needing more hot I had to turn down the cold and increase the hot.
I also found the bathroom basin was more of an issue with the knocking / hammer issue (although it does happen with them all).

I adjusted the main a couple times clockwise which is closer to the ‘turn off’ and it seems to have helped the shower hot tap now only needing one full turn so thank you for that.
ige noticed the hot tap on the basin isn’t knocking but I will monitor.
if it continues, would this suggest the pressure is still alittle too high?

Newgreenthumb

@EricL

i assume at the main, the more you turn it anti clockwise, the more pressure?

thank you for your time.

EricL

Hi @Newgreenthumb

Knocking is often caused by the sudden closure of the tap. I suggest trying this exercise, slowly open and slowly close the tap. If you still get knocking, I suggest replacing your jumper valves with 2 x HydroSeal Anti-Hammer O-Ring Tap Valves. You can also install a Sioux Chief 15mm Size A Hydra-Rester Water Hammer Arrestor With Conetite Tee. Another alternative would be to place Doust 15mm Male And Female Anti Hammer Water Saver Adaptor Valve.

These devices are designed to slow the water down or absorb the intense water pressure generated inside your plumbing system. In reference to your other question, turning the valve anti-clockwise opens the gate further.

Please keep us updated with your progress, we look forward to seeing your tap pressure balanced.

If you need further assistance, please let us know.

Eric

Newgreenthumb

Hi @EricL … indoor have any knocking during or closing taps, only turning on. I did use the method for air pockets but turning on taps from lowest point to highest etc that seemed to work ok for a couple weeks but it is now back. I may have to engage a plumber in case there is some other issues, going on.
thank you

MitchellMc

I'd agree that some further investigation by a plumber sounds like a good option @Newgreenthumb. You could require a water hammer arrestor to be installed. However, the need is generally qualified by knocking whilst turning valves off, not turning them on.

Keep us updated as I trust many of our members will be interested in hearing your results.

Mitchell

ThePredator

The pressure remains constant. It is not a function of how far the property main tap is turned. Imagine an air supply valve. You have a set pressure from the air reservoir. You cannot reduce the pressure in the vessel being filled unless you turn the inlet tap off at the pressure you desire. Exactly the same for a commercial or domestic water supply unless you fit a pressure reducing valve.

I have done a lot of work with farm property supplies fed from bores.

Ideally, and only for the cold water supply, a water pressure tank takes the hammer effect off loose pipes. If your problem is the cold water line, this should work.

Another problem is sharp bends in pipes. Not an ideal situation when you experience water hammer but it's the reality of plumbing inside house walls.

At the moment, with our most recent property, I'm installing Sioux Chief arrestors on the hot water lines supplying our dishwasher and washing machine.

Interestingly, there is a T-piece at the sink mixer tap - washing machine take off point. If I put the Sioux Chief on the t-piece outlet to the dishwasher, the constant spray-stop action that the dishwasher does during the cycle no longer causes a shock wave in the hotwater pipe. However if I move the arrestor to before the T-piece input, the mixer tap shock wave is not arrested, but the dishwasher shock wave is. Go Figure !!

One explanation may be the reverse flow protection action in the in-line tap directly feeding the dishwasher from the outlet of the t-piece. There may be a slowing of the back pressure here, slower than the quick hand flick off of the mixer.

MikeTNZ

Hi @Newgreenthumb,

Generally the main valve (stopcock) at the road or near the entry to your building is normally opened all the way and bought back a quarter of a turn.

This ensures maximum pressure, but also makes sure that the valve stem doesn't lock in the fully open position like some brass valves have a habit of doing.

It may pay to have a registered plumber have a look at this, they will be able to tell you off the top of their head what the issue is.

Having said that, they could test your static and dynamic pressures with a proper gauge, it almost sounds like there is an Ajax (pressure-reducing) valve in the main line to your house (after the main valve) that is incorrectly set (as in too high) if you're having issues with water hammer when you open a tap.

Again, they will be able to tell you yay or nay as to what the issue actually is.

Let us know how you get on.

Cheers,

Mike T.

ThePredator

Agree. I wonder if you have seen any instances of banging in the pipe run before the pressure reducing valve section ? Depending of course where the PR valve is fitted....close to the main water valve or close to the main line at the house foundation itself/

MikeTNZ

Hi @ThePredator,

A very good point, with pipework within a house or whatevever, it is very hard to locate where a given noise/shockwave might be coming from, due to the pipes actually transmitting the noise throughout their length.

Now, I could be wrong about Australia, but over here in NZ, it is convention that the Ajax valve is installed in the hot water cylinder cupboard where the cold water main is bought into the house, provided of course that it isn't outside because it's run on Gas.

Don't hold me to that though, it all depends on who plumbed the house when it was built, with a concrete slab floor house, it will be where the main comes through the floor, somewhere.....

Child Item