PRESSURE REDUCER (or regulator)

1 Principle of small reducers
100_1774
2 Utility

    2.1 The distribution of the drinking water
    2.2 Reduction of the average pressure
    2.3 Elimination of the pressure "accidents"
    2.4 Non-return of water
    2.5 Regulation

3 Choices of a model

    3.1 The Diameter (Rolling of the seat)
    3.2 The curves flow/pressure of model
    3.3 The mechanical stand
    3.4 Pressure manometer
    3.5 Quality

4 Sites

    4.1 Just after counter
    4.2 A water tap high pressure
    4.3 Only on the water-heater (or the boiler)

5 Breakdowns

    5.1 Which age has your reducer?
    5.2 No water!
    5.3 The water-heaters flow permanently
    5.4 The pressure mounts slowly
    5.5 My water-heaters slowly flow only night

        5.5.1 You do not have a pressure reducer
        5.5.2 You have a pressure reducer

    5.6 Origin of the breakdowns and comportment
    5.7 Just after work on water network, my water-heater flow

6 Adjustment of the pressure

7 Stories to laugh at it

8 I put one of them? or I do not put any?

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Preface

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1 Principle of the small reducers

On the photograph one can see top downwards: the lid, the nut centring device allowing the compression of the spring, the membrane assembled on the clamp, on the left one sees carries it valve with its axis of centering, the tank (pot) with very visible the seat of water arrival, then all in bottom the stopper of the bottom, being used at the same time with cleaning and as centering for the axis of the door valve. To notice one of both small holes in skew, of which the use makes it possible the mobile equipment to go down at a certain speed (damping) and to avoid thus very put in oscillation of the mechanism. Water arrives by an internal pipe at the "pot" (on the right), on the seat "of a tap". In front of this seat a valve 100_1775interdependent of a clamp is ordered by two antagonistic forces: The spring located partly high (where there is the adjustable screw) operate a force on a rubber membrane which receives the pressure of use. This force tends to open the passage to water contrary to the force of the membrane. (The force on a surface of 24 cm2 for 3 bars of pressure makes 73 KG nevertheless!) The clamp is guided partly high by the membrane, and partly low by a small plunging axis in a boring located partly low of the lower stopper of the "pot". In certain marks, a small opening in the cone, side spring allows the setting the free air on a the upper side of the membrane and thus authorizes displacements without compression of the air. Here it is simply the nut centring device of the spring partly higher which provides this function. Like it was known as, an adjustable screw makes it possible to adjust the pressure in the particular installation.

2 Utility

2.1 The distribution of drinking water

The physical principle wants that each subscriber does not have the same pressure as his neighbor, mainly when altitudes are different. (There are also the pressure losses) This physical aspect is awkward but can be circumvented by the local lowering of the pressure. (One cannot increase in a simple way a pressure). This is why, the drinking water distributors always leave with the highest pressure to be able to satisfy all the users.

2.2 Reduction of the average pressure

The pressure reducers are thus intended initially to reduce the average pressure so that this one is acceptable for the whole of the domestic apparatuses.

2.3 Elimination of the pressure "accidents"

The water distributors use also pressure reducers, mainly when it is possible to take a whole succession of points of distribution, in the direction of a constant fall of altitude. The lower one is compared to the tank, the more the pressure is high. The distributor thus installs an apparatus of this type (much larger). It can arrive, (as it is the case at the subscriber), than these apparatuses release. Then the pressure of the whole of the network goes up.

That is translated on your premise by the water-heater which flow with the group of safety, even a flood... If you do not see it, you will realize some at the time of the next invoice, because this water passes to your counter. In general the distributor realizes problem rather quickly and cures it obviously. If you are protected yourself by a pressure reducer, (which functions) you will not have to undergo all these troubles. It should be recalled that a group of safety must imperatively be connected to a discharge pipe with the free air of strong section (minimum 32, recommended into 40). If your plumber did not respect that, your insurance will refuse to compensate you, because the installation was not carried out according to the good rules.

2.4 Non-return of water

Of share its principle, a pressure reducer also acts like a non-return valve. Indeed if the membrane receives a pressure higher than the pressure of entry, the membrane will draw the clamp with the valve on the seat, thus preventing the return of water.

2.5 Regulation

Actually in addition to the reduction of pressure, this apparatus controls the pressure of exit, some are the variations of pressure in entry (there are limits nevertheless!) When your public network is not stable on the level instantaneous pressure, do not hesitate to make this expenditure. This type of reducer ensures of a fastest response time, vis-a-vis with a variation of pressure.

3 Choices of a model

3.1 The Diameter (Rolling of the seat)

All these apparatuses are delicate and can wear quickly if they are badly given. Without going into the great hydraulic theories that I control badly besides, the drainage duct between valve and seat are the place of an important rolling if the opening is small. That can even become the equivalent of a "mini slicer". To avoid that an apparatus should be chosen having a profile of seat perfectly studied to resist rolling, and especially to choose the good apparatus, adapted to the domestic flows. The ideal solution is to know its medium flow and of point and to choose the apparatus according to that on the curves of the manufacturer. Thus ask the salesman the curves... do not seek it, it left to call the police force immediately, because it took to you for extraterrestrial...! More prosaically, one always recommends going down from a diameter, compared to the diameter of the pipe. But that does not represent large-thing for you! Then if you did not find anything in the manufacturer mount a reducer of a diameter ½ inch if you are a responsible ecological user. If on the contrary, you are a water large-scale consumer mount a reducer of ¾ of inch.

3.2 The curves flow/pressure of model

If by chance you have the curves of flow-rate pressure, it may be that you cannot obtain the reduction of pressure desired because of little pressure to reduce and of the flows requested. In this case it is to better give up, even if the use of the reducer were envisaged in the event of accidental overpressure on the network. This wants simply to say that your pressure of arrival remains rather low.

3.3 The mechanical stand

The pressure reducer is a relatively heavy part, and it is useful to make it at least rest on a plate, to avoid tiring all piping. A flexible lock ("SERFLEX" i.e.) preventing it from raising plate would be one more. Then, the Manufacturers, to put a mounting foot to fasten it with a wall would not be a luxury. Mechanically it would be nevertheless better than to see the apparatus jumping in the air at the time of abrupt stops, or water hammers.

3.4 Pessure manometer

This is not obligatory, but..... You are happy to have a fuel gauge on your car? Then a manometer on the reducer, you mount will know thus if all occurs correctly.... (To take in this case a model having the catch planned for this use).

3.5 Quality

It is a very important point, because on that your peace will depend. Always take a model NF (French Standards). In the worst case that a flood will avoid you, and an "at least worse" water invoice, "salted".

4 Sites

4.1 Just after counter

In this case all the installation will be in reduced pressure. It is well, but to wash the car it is perhaps awkward? For are the cabin of hydro massage, there specifications of pressure minimum (it is necessary to refer to it) Incompatibility with the groups of safety? I do not think because is needed nevertheless hot water. If there is a man-hole of rather large external counting, to bush this reducer right AFTER counter and of purging that will protect at the same time the buried pipe of possible overpressures. (See afterwards for fuller precise details) All the valves of taps are protected, and it is not necessary "to tighten with dead" these old valve taps.

4.2 A water tap high pressure

To keep a point high pressure is always of interest, because like evoked in beginning, it is not easy "to go up" a too low pressure. All depends on the configuration which you have, but service valves with direct pressure network are very useful for the car and the garden... This is often incompatible with the protection of the pipe buried from the counter to the house. It is with you to see, but if the installation is recent with a good pipe PEHD bandages blue 16 bars, there is no problem. This configuration protects also the interior installation and the valves from taps.

4.3 Only on the water-heater (or the boiler)

It is also an interesting solution, because in the event of low pressure of the network, that does not deprive the other cold water uses of a pressure a little higher. It should be noticed that they are heating water (or production of hot water per boiler) which is the first problems appearing with overpressures. The other problems are only problems of mechanical resistance of elements (pipes, taps... etc). In general these breaking strengths are very high and about 16 to 25 bars or more.

5 Breakdown

5.1 Which age have your reducer?

A good response beside the subject is better than long speeches...!

Await from your car that it makes 2 million kilometers without breakdown?

That depends on the request of the apparatus, and of the type of water (pH, limestone, Suspended matter, sand... etc) but in general, 20 years represent one lifespan maximum (with the proviso of having a water of correct physicochemical qualities).

5.2 No water

To refer to the § 5.1. A new apparatus cannot except do that to you on rupture within the competence of compensation. It is especially the manifestation of the very old apparatuses. For an old apparatus, the spring is in general the cause of this problem, because it is oxidized so much that it east loses shape and becomes inoperative. There can also be a sand grain which slips into boring guides in bottom of the "pot", but it is rarer.

5.3 The water-heaters flow permanently

runs the case of leakage to the water-heater reveals an absence of regulation of pressure, and if there is a pressure gauge at exit, and that pressure close 5.5 bars without water pulling, the groups of safety can start to flee with this value. Attention with the plumbers, they are the crafty one which you "will stick" a group of safety to be changed. That will go one year or two then "again!". The plumber not missing to say "it is fault of the Service of water which sends water hammers". Not Mister! I am impartial, because it is you who do not control your job, by an obvious lack of knowledge. In 99% of the cases, it acts of the pressure reducer which does not react correctly any more, for the following principal reason: The seat of the reducer was rolled by high throughput speeds. There are then slits like kerfs to metals on the seat. Of course like there is escape, the pressure goes up and the water-heater flow with the group of safety. Oh that can not much not run because it is limited by the section of the slit of the seat.
FOOT-NOTE: When an heating water is not of "heats", the group should not flow! In some cases, the low guidance of the clamp is in question, but it is rarer

5.4 The pressure mounts slowly

This case is often the reflection of a general wear, and often the rolling of the seat or the wear of the valve rubber is in question. That results in a weight a little higher to the opening of a tap, then a split second afterwards that becomes again normal. There too it will be necessary to think of changing the apparatus. The rise in pressure is done over a few seconds. If you have a pressure gauge that sees very well!

5.5 My water-heater flow only night

5.5.1 You do not have a pressure reducer

It is an answer which would not take place to be in this article but the explanation will apply to the following paragraph: The distribution of drinking water is subjected to the pressure losses, (as in electricity with the resistance of the drivers). These pressure losses result in a general fall of the pressure of the network during the hours of great consumption. In middle of the night, the phenomenon of the pressure losses is extremely reduced by the fact that there is only very little consumption. The pressure thus goes up slightly. This night rise is sometimes increased very slightly also by the pressure of the pumps (case of the networks in repression distribution). That is enough to gain sometimes up to 1 bars moreover. Result if one is in limit, the water-heater is happy to show that there exists (That is seen well on the invoice!) If you have a doubt, raise your counter before laying down you (all the digit until the litters) and before drawing hunting from water of the WC the morning, do not forget to raise the counter. The no null difference of the two values, indicates a problem...

5.5.2 You have pressure reducer

Read above the explanations because they apply entirely. But then... Eh well it is the fault with the reducer which would have to compensate for the variation of the network and which did not do it.

5.6 Origin of the breakdowns and comportment

- The corroded and softened spring causes a closing of the valve or a strong reduction of the flow. Elasticity is only partial, and if you try to screw the adjustable screw, then you will make worse than previously because you will not have water any more. Explanations: the spring completely folded or broke! One seldom finds springs treated anti-corrosion for the replacement... I can nothing there! I deplore it! It is necessary all to change!
- the dézinsification (common use in France translated by "Zinc carrying out". Now read "dezin" to simplify), that exists and that touches several elements of the reducer. The characteristic of this term is simple. Brass is a zinc and copper alloy. Zinc manages to migrate towards outside and it does not remain any more whereas the copper which is a soft metal. This dézin... is noticed by the red colour brown (copper) which appears on certain parts. The seat becomes red brown then and cracks quickly because of rolling. The lower locating spigot is completely dézin... and there is no more regulation with null flow, because the clamp either is blocked in boring, or it authorizes nonparallel movements between the seat and the valve. Under operation with medium flow and important, there is however regulation. The change is nevertheless impossible to circumvent in this case.
- the rubber valve wears, and its surface is not plane any more, the pressure manages to go up by the escapes, but when there is flow, operation is correct. It is rather identical like demonstration to the split clapper seat. This operation on the traditional models in the shape of pot is rather easy (a simple screw). On the model photographed in spare parts, one needs small tools special for pin. I think that that is playable and that success is only confirmed once on two, because one is often obliged "to bludgeon" to arrive at his ends...
- the membrane is bored! This case results in a higher pressure into exit and an escape on the small hole of setting to the free air on the level of the spring. This case remains very rare, because the membranes are very solid. If you find a membrane, or if you want to do one of them it is possible, but attention to center it well such as it was front. It is necessary at the same time to change the valve rubber to ensure themselves of later a correct operation, and to check that the seat is in perfect state (absence of kerfs). It is very delicate even for the professional. I recommend to change the apparatus!

5.7 Just after work on water network, my water-heater flow

In the large majority of the cases, work of adduction put a hard test to the old reducers. Of course, the demonstration is the water-heater which flow! It is not the group of safety (or it is very very rare!) it is the reducer which releases because of the air present in the conduits and which will result in water hammers. That is explained as follows: The membrane before work worked in a weak beach of variations, and all occurred well. Since work the reducer has to correct great variations due to the water hammers of the air. That resulted in an important race of the moving element of the clamp. The spring was obliged to go further in its deformations. As the spring is completely rusted, it lost shape and the reducer does not function any more. The fault is not in general to defer on the water distributor but only on the out datedness of the apparatus which was installed. If all times the apparatus were new or recent, then it is different!

6 Adjustment of the pressure

In general for the models in the shape of pot with a higher cone, it is necessary "to screw" the screw to increase the pressure and reciprocally. (This operation can be a real failure if the reducer is too old, because there can be break-in of the spring and any more of water!) Certain cheap models do not even have a possible adjustment, they are so small that one would believe that is to play the doll's tea party. Out of drinking water one should not joke with quality. Change this model quickly! Models NF are always preferable.

7 Stories to laugh at it

I am unfortunately obliged to say evil of some plumbers, but they deserve it sometimes. After triple exchanges of pressure reducer decided by a plumber, an subscriber addressed itself to his dealer, with a little very correct irritation but however. When this subscriber opened a tap, it took a serious weight, then after that normal... the trade of plumbing became again is not completely that of drinking water! To help an subscriber unresolved having a real problem, I look at and I record the pressure over 12 midnight. It was right with the autumn, at the moment or one relights the heating. On the graph one clearly saw enormous variations of pressure in salvos... Suspicions of the heating! Indeed the cold water and domestic hot water circuits communicated and the group of safety was badly placed. But before there was nothing, then why of only one blow? Eh well, the water counter had been changed and a VALVE had been put, thus preventing any water return towards the network. These subscribers thus had the hot water pressure in cold water, with in more one enormous risk of rupture in the installation. And I have others of them also "crusty"...

8 I put one of them? or I do not put any?

If your pressure of public network does not exceed 3 bars approximately, I do not advise to put some, for 3 reasons: This pressure thus remains always lower than the 6 usual bars of the groups of safety of heating water initially, in second place on account of the comfort of use, and finally because the reducer would be doubtless in an operating range unsuited and thus destroying for the apparatus. If your pressure is located between 4 and 6 bars, it is useful to put one of them, and I would readily position it on the only circuit of heating water. If the pressure is higher than 6 bars, I recommend to preferably put the reducer at the general arrival with a system high pressure for the car and the garden. Then between 3 and 4 bars? I do not know too much, because the reducer works badly "to remove a small bar" and this pressure of 4 bars is "generous", but not awkward... I believe that I would not put any! To note that it is useless in the near total of the cases to put two reducers in series, because there will be of them always one which will not have work to make and which will worsen. Note that usually a dealer always warns his subscribers of an increase in pressure, and that in this case, it is always necessary to re-examine the forks of pressures above, and doubtless to go towards the installation this time of a reducer even of its change if it is old...

Hold with the fact I would take a good half PRESSURE beer well (without reducer)!

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