Paphos People

The winter, after Zelemenos area stop buying water from Vesta company, our main water pressure rises to 9 bars (I have the meter installed).

An inlet valve at top water tank cannot hold such pressure anymore and water constantly over-spilling.
I did talk to Vesta guy and he said the pressure should stay at 3-4 bars level.

What need to do with the issue ?

I suggest you get a plumber to fit a pressure reducing/control valve at the mains input point to your property asap. Won't cost much but will prevent you having burst pipe joints and water cylinders!

When fitting a pressure regulator/ reducer to the main house supply It should be noted that the smaller units will also restrict the water flow too, slow running hose pipe or drinking water tap etc, it would be best to avoid 1/2" units and have a 3/4" or 1" unit fitted although they are more expensive it is worth the extra. In time the regulator will jam, dont hit it with a spanner, dismantle it and clean out the lime scale as this works much better. unfortunately if you have a water softner fitted then the regulator needs to protect the softner from excess pressure so the regulator cant be fed with soft water.

that's good note, unfortunately most of house's cold pipes are 1/2", so the e7 difference in its price getting 3/4" (e22 vs e29) does not procure it

I assume that you have a tap where the water enters your meter, we have, could you not just turn this tap down till you have an appropriate pressure.

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Time wounds all Heels

Yes, every main entry has main valve (before a meter); the problem is static pressure, eg when no water use in the household. Then the pressure [9 bars] come straight to that valve at water tank, which is not design/built for it. So, we have the low constant overflow in the tank.
Main valve do not affect the static pressure, it would create drop in dynamic level when water will flow. Side effect would be a significant reduce the flow. You can use simple (and right) analogy: a circuit, a voltage and resistors.

That will not reduce the pressure, only restrict the flow, Do as Mouse suggested and get a good quality Pressure Reducing Valve fitted. I fitted one at our place as we had 9 bar and it only took half an hour or so and the pressure is now just under 3 bar; Arenco in the main bus station should stock them.

Jim

Yes , Arenco or Panthemiki both stock them.
The fact that many mains water pipes are 1/2" doesnt matter as adapters are cheap and easily fitted.
On the packaging of the pressure regulators they rarley quote the maximum flow rate, 1/2"units often will restrict the flow on the water main, so buy a physically larger unit that will have a larger peak flow, hence the 3/4" or 1" fitting.

Turning valve off partially to reduce pressure, its not so simple, there is static water pressure and running or dynamic water pressure.
static water is when no water is being used, when it is still.
Explained simply Running water pressure will vary with flow, faster the flow the lower the pressure, to many varibles to dicuss here. I have met plumbers that dont understand this concept.
This problem is also true of pumps for pressuring your water system. some pumps sold are high pressure but not a high flow rate and so as the flow increases the pressure drops, this will not be a suitable pump and I have seen many fitted here. what you need is a fairly low pressure pump of about 3 to 4 bar but will supply this pressure at at high rate of flow. If your pump needs a pressure reducing valve then they fitted the WRONG one.

So far I'm reading on a few boxes and leaflets the max pressure is 25 bars.

Sergio, I hate to think what might happen if you subjected a domestic (Cypriot) plastic water pipe system to 25 bars of pressure!! (That is 367.5 lbs/square inch in old English measure!).

That's a pressure regulator made form a brass. So, the max pressure value [25 bars] is applicable only to it.

Not telling about plastic tubes (to be honest you should know there are high pressure tubes made from plastic and metal mesh what does withstanding higher water pressure then 25 bars).

Now back to a solution.

I'm stuck with much more complicated task, as the standard water box have no spare space inside for install the regulator.
Plus, both metal tubes come straight from ground. See a picture. Bummer !

The pipe must reappear somewhere inside your property (perhaps under the sink in the kitchen) where you might find enough space. Failing that a good plumber would no doubt be able to do a work around after the water meter (which is what I assume the round object in the pipework is).

I would like to see real installs in typical water box all three parts: a main valve, a meter and a regulator.

As an engineer, I did try to make drawing of such install and come to a conclusion: the 1/2" pipes, 90 degree connectors and other parts doesn't fit in the space, regardless your or plumber's creativity. It's just designed with minimalist approach: a valve and a meter, so the short distance between two pipes defined by that two too.

The box's outlet metal pipe turned into plastic one somewhere inside a divider wall, then it has T-connection to irrigation/garden hose outlets, then has in a few meters a split (inside of foundation ?) to two ways - one is connecting to sink's facet, other - to a top water tank's valve.

Sergio the layout in your picture shows the installation to be quite old and I am as yet to find an elegant solution to your problem. the 2 1/2" steel pipes go down about 50cm and connect to probably the black flexible pipe. Hopefully your mains inlet comes in on the right to the valve and then to the meter although this may not be the case.
Presented with your problem I would disconnect the meter on the left side, turn the meter diagonally, take the meter adapter off the left pipe and fit the regulator to this. remove 90 from left pipe and discard, put 15mm starter on left pipe and then make up from this to far end of regulator with solder or compression 15mm copper fittings. I dont recommend flexy pipes as they tend to fail. This is not pretty but options are limited.
hope you can understand what im getting at.

Honestly not yet, perhaps you could make a sketch and I'll put measured values to it ?

Dig the Box out and modify your pipework and then cast a new bigger box around the new pipework.

Jim

The space is tight, the box barely fit between a retention wall and a walkway :(.

Could you not extend everything vertically, including eventually the height of the box. You could then fit the regulator into the extended vertical pipework ?

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Time wounds all Heels

Good lateral thinking Hermes

Well, vertically not - the current clearance is less then 1" from top of the meter, but !

Your idea did spring my own design ... let me measure all parts ... if it'll fit ...

But if you extend the box vertically surely you increase the clearance

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Time wounds all Heels

My plumbing skills are far superior to my artistic skills I apologise for the quality of the drawing
the 15mm pipe is very much suck it and see, you need a couple of straight starters, solder elbows, solder 45's sraight pipe and maybe a bit with a small bend in it, then mix and match til it fits !!!!
The adapter with a 3/4" nut one end and a 1/2" thread the other are available in short lengths, this may help squeeze things in. When turning the meter you must hold the right pipe with grips so as not to disturb the joint deep in the ground.
just realised I dont know how to post a pic, give me a few mins !!!

Thank you for the sketch, looks doable - I'll make all measures and play with the design on a paper (1:1) to check if everything will fit in the box.