Cold water pressure reducer??

[chocccie]

Hi there

 

I am fitting plumbing to my house.  I am getting some dripping from a couple of joints.  It is a plastic flexible system with compression joints. It is the cold water pipes.   I have searched old threads but can't find an answer to my question which is....

Should I put a pressure limiter on the cold water system or is it just for the cold water that enters the chauffe eau..

thanks

[Nick Trollope]

[quote user="chocccie"]

Hi there

 

I am fitting plumbing to my house.  I am getting some dripping from a couple of joints.  It is a plastic flexible system with compression joints. It is the cold water pipes.   I have searched old threads but can't find an answer to my question which is....

Should I put a pressure limiter on the cold water system or is it just for the cold water that enters the chauffe eau..

thanks

[/quote]

PER (if that is what you are using) is good for about 10bar, so I'd fix the drips!

You shouldn't feed your C-E with anything more than 4 bar and if the mains pressure is higher than this, there is nothing to stop you reducing the pressure to the whole system (which should be designed/built to be happy at 6 bar).

 

 

[clarksinfrance]

Silly question I know, but worth asking. Did you use the sleeve inserts on the joints?

[Gyn_Paul]

"...You shouldn't feed your C-E with anything more than 4 bar..."

Otherwise the Groupe de securitie on the chauffeau will never be done

dripping. It's just loud enough to hear when you're nearby, and all the

time you will have the image of the little wheel in the water meter

going round and round !

p

[londoneye]

Ours drips non-stop - we are now up to emptying the bucket about once every two days - we keep meaning to do something about it, but have never got around to it - too much else going on.     Never cnsidered it might be water pressure though ...

[Nick Trollope]

A few asides - the GdS on your chauffe-eau should only drip when it is heating. A bucket is not an ideal drain (or even legal, something to do with legionaires disease).

PER (the most popular plastic plumbing here) does not use inserts, the support is built into the joint.

But the OP hasn't told us what he is using, making it quite difficult to advise....

[Gastines]

2 houses ago , we had a knocking noise from the waterpipes first thing in the morning. I used to whizz round flushing loos and running taps as we did B&B and it started about 7.00 AM, and didn't want guests complaining. I had   had a plumber recently install a shower in a gite joining the house and was convinced it was water hammer and the pipes, although I was sure I lagged them, knocking. I had tiled the shower enclosure  and to solve the problem,or try to, actually ripped the tiles and boarding off where the pipe run was to make sure they were well lagged and not touching.. After all this the neighbour kindly informed me that they increase the water pressure  end July/ August because of the increase in water consumption due to the influx of holiday makers and holiday home owners.!!!!!

Now I think it's the norm to have a pressure govenor fitted and I think it is obligatory.

Plumbing is not one of my strongpoints,there are many others.

Regards.

[chocccie]

Hi there

Sorry for not getting back...been off line for a couple of days.

Thanks for the advice nick.  Joints are now drip free. except for the main pipe into the house.  I fiitted new stopcock and adapter which then joins the 25mm water pipe to a 4 way manifold.  I have taken them apart and put them together but am still getting a slow drip each end(about every two seconds) not bad considering how much pressure there is.  I am going to measure the water flow over a minute to calulate pressue in case it is excessive.

Yes in the house itself I am using "easy plombiere" per system.  so no inserts required.  Are the different per systems intercangable.  I ask as my brico has been out of stock of a couple of the items I need for a while.

Thanks again for the advice nick

[Nick Trollope]

Pressure guages are pretty cheap - I have plumbed them in permanently on a couple of occasions.

Your PER fittings should not leak - are you using PTFE tap or hemp (you shouldn't)?

Braodly speaking, the fittings are interchangeable - credit it or not, I find that the Bricodepot ones are amongst the best.

BTW, whilst I am registered as a plumber (because it was free..), I do hardly any and what I do do is in PER. Don't take my word as Gospel...

 

[Grumpy]

Nick,

the implication of your reply is that drips from the bottom of a chauffe eau are not only to be expected but are part of its correct functioning. Is this so? Ours drips when the heater is switched on.

Cheers

Steve

[Nick Trollope]

[quote user="Nick Trollope"]

A few asides - the GdS on your chauffe-eau should only drip when it is heating. 

[/quote]

That is what I said - and believe to be true.

To expand the comment slightly - it is normal, indeed part of the functionality of the chauffe-eau (and fluid dynamics) for the heater to drip whilst heating.

 

[Chancer]

Boyles law, or was it Charles Law?

P1*V1/T1 = P2*V2/T2

[Nick Trollope]

[quote user="J.R."]

Boyles law, or was it Charles Law?

P1*V1/T1 = P2*V2/T2

[/quote]

Or neither or both? Boyle - P/V= k & Charles - V/T=k. Of course, both Boyle & Charles were considering ideal gasses.Bernoulli perhaps?

PS. I really don't know what I am on about.

 

[Gluestick]

Boyles and Charles are gas laws:  there quite a few others!

http://www.bcpl.net/~kdrews/kmt/gaslaws1.html

However with a chauffe eau  -   unless something awful is up with the thermostat and the ballon is full of super-heated steam!  -  one is dealing simply with expansion caused by heat. The safety valve drips when the heating element is on and is hot!

 

[Gyn_Paul]

The volume of the water in the chauffeau expands as its heated. I used

to know how much but I can't remember: something like 4% from 15C to

65C. The GdeS is a spring-loaded device which allows water to seep out

and down the drain (at least there should be a drain, rather

than a bucket) as the pressure rises. What I suspect happens with one

which continues to drip is that the incoming static head is just below

the point where it would overcome the spring resistance, so it stays

closed when it is first filled. Then when it is heated, it opens

sufficiently to allow the excess to drain away. However the difference

between the two pressure states is so small that the valves doesn't

seat again properly. Sometimes when a little hot is drawn off is cloes

properly; sometimes not.

I went to great trouble to change a dripping GdeS, thinking it was old

and corroded, only to find that the new Teflon-coated replacement

dripped just as badly. An identical model fittled to another chauffeau

- but pumped from the well rather than connected to the mains - doesn't

drip except when heating up.

p

[Grumpy]

Thank you both, Paul & Nick, you have just saved me from changing the chauffe-eau - something to which I was not looking forward! Steve

[Le Plombier]

The GDS should not drip or run, only in an emergency when the system is over pressure, the GDS is preset to discharge at 7bar pressure

Your GDS is either being activated by over pressure or is faulty, it is easy to check for excess pressure, next time the GDS is running open a tap to relieve the pressure and check the GDS has stopped dripping. If it does not stop the GDS is faulty and should be replaced.

If it stops then you need to monitor system pressure when cold and when hot.

You should have a pressure reducing valve at the point of entry of the water main in to your house. Some of these are adjustable but they are all factory preset to 3bar which is the correct pressure.

If you do not have one fit a pressure reducing valve and monitor the GDS, this should solve the problem

If the GDS continues to dischage when the chauffe eau is hot this is due to pressure build up caused by the expanded volume of water

This can be solved by installing a vase de expansion on the system. The vase has a pressurised diaphragm inside and it will accomodate the expanded water volume with little or no resultant rise in pressure. If you fit a vase de expansion make sure you get one suitable for installation in a secondary water supply and not a normal heating one.

A constantly or intermittently discharging GDS is wasteful of water and is not acceptable

 

[Nick Trollope]

M. le plombier is quite right, of course. Wasting water is not acceptable, so an expansion vessel is the right thing to do.

However, according to what is normal and the normes, over-pressurisation in a chauffe-eau can be wasted and does not represent a fault condition, as he implies.

 

[Le Plombier]

Part of the function of the GDS is as a pressure relief valve

The function of a pressure relief valve is purely to discharge in the event of over pressure to protect the system equipment and prevent damage.

If your pressure relief valve is regularly discharging and you have a problem with your system

Would you accept the pressure relief valve on your heating installation discharging all the time?

If your system is over pressurising you should take remedial action to correct the reason for the over pressure

I never leave any of my clients with this problem and I get plenty of calls from homeowners who have the problem and are trying to eliminate it.

Leave a tap dribbling for 24 hours and measure on your meter how much water you have wasted, the water discharging from your GDS comes through the meter as well 

Le Plombier

[Nick Trollope]

Right again, but;

[quote user="Nick Trollope"]

However, according to what is normal and the normes, over-pressurisation in a chauffe-eau can be wasted and does not represent a fault condition, as he implies.

[/quote]

I'm afraid.

Water expands when heated and, if the chauffe-eau is sealed and the steel casing is inflexible, then regardless of the pressure of the tank to start with, the water must go somewhere. See Mr Bernoulli, above.

This is why GDS's have traps on them. Have you tried using a GDS trap to evacuate a C-E? Water everywhere!

 

 

[Le Plombier]

I frequently drain chauffe eau's using the GDS as this is one of the functions the valve is designed to perform

It is a shut off valve, a drain valve and a safety pressure relief valve

As it connects direct to the chauffe eau I would like to see you drain the chauffe eau any other way unless you have fitted a stopcock and drain cock in the supply before the GDS

Incorectly installed hot water installations result in over pressure

Install them properly and this problem does not occur and you do not waste lots of water, water you have spent a small fortune heating in the first place

Le Plombier 

[Chancer]

[quote user="Le Plombier"]

I frequently drain chauffe eau's using the GDS as this is one of the functions the valve is designed to perform

It is a shut off valve, a drain valve and a safety pressure relief valve

As it connects direct to the chauffe eau I would like to see you drain the chauffe eau any other way unless you have fitted a stopcock and drain cock in the supply before the GDS

Le Plombier 

[/quote]

 

I dont think that you would not be able to drain a CE in that way because the GDS is a one way valve, I have only been able to drain them by operating or removing the GDS.

When you think about it if there was not a valve then the heated reserve of water could mix with the incoming potable mains water with the risk of bacterial contamination.

If there was not a valve then the increase in pressure or heating expansion would just displace back the incoming supply and not require a GDS.

Ironically I was thinking of this this morning when my mains pressure fell (as it often does) while I was washing, the cold feed reduced to about 1/2 its pressure/flow whereas the hot came out with an initial burst of residual pressure from the ballon before doing the same proving the existence of the valve. - I think!

Nick

Yes it makes a horrible mess due to the air channels above the U-trap, I have yet to work out what they are there for unless it is create an airgap to prevent fluid contact between the cylinder contents (although only when purging) and the drains.

In my region GDS often drip after a while because of the calc in the water, I often find that the valve can be reseated by purging a few times which stops the dripping for several months, I have not yet paid out for a teflon coated one, do they still drip after a while?

Somewhere I have the fitting instructions for the CE which state the volume of water displaced under heating, it was minimal cerainly less than a couple of 100 ccs, less than many people waste brushing their teeth, I calculated that the cost of an expansion vase would take more than acentury to recoup given that I pay 1 euro per cubic metre or 1000 litres for water.

Now if it were bottled water that I were paying for I would have an expansion vase - on second thoughts it would be cheaper to have mains beer!

[Le Plombier]

For the sake of clarity the GDS IS A TRIPLE FUNCTION VALVE !

IT IS A SHUT OFF VALVE

IT IS A PRESSURE RELIEF VALVE

IT IS A DRAIN VALVE

If it does not shut off the supply to your chauffe eau it is clearly fitted incorrectly

When you drain a chauffe eau it is normal practice, for those who know what they are doing, is to break the joint on the hot outlet on top of the chauffe eau. This allows air to replace the draining water and, surprise, surprise, the chauffe eau drains perfectly

It is also not accepted practice for the GDS to discharge all the time, if this happens your system is over pressurising and a remedy should be sought

Le PLombier

[Chancer]

[quote user="Le Plombier"]

For the sake of clarity the GDS IS A TRIPLE FUNCTION VALVE !

IT IS A SHUT OFF VALVE

IT IS A PRESSURE RELIEF VALVE

IT IS A DRAIN VALVE

If it does not shut off the supply to your chauffe eau it is clearly fitted incorrectly

When you drain a chauffe eau it is normal practice, for those who know what they are doing, is to break the joint on the hot outlet on top of the chauffe eau. This allows air to replace the draining water and, surprise, surprise, the chauffe eau drains perfectly

It is also not accepted practice for the GDS to discharge all the time, if this happens your system is over pressurising and a remedy should be sought

Le PLombier

[/quote]

Using upper case to shout does not make what you had already posted (which incidentally I understood and did not disagree with) any clearer.

I assume that the message "for those who know what they are doing" and "surprise surprise" was meant for others as I have not encountered a problem draining one and prefer to open an adjacent hot tap.