In the tap water pipe networks of buildings pressure variations disturbing and preventing the measurings occur. Remarkable causes for pressure variations are the temperature changes in the water of the hot water system. The changes in temperature come about e. g. from the on/off functions of the heating couplings and the consumption variations of the hot water. The night electricity accumulators cause major temperature changes also in the night-time. These temperature changes cause in their turn pressure variations.

The changes in pressure vary from the preset value of the service pressure to the opening pressure of the safety valve, for instance 10 bar, especially in the electricity accumulators operated according to the reservoir principle, which clearly have become more common.

A common minor disturbance factor is a between the cold and hot water pipe network installed, regulations fulfilling one-way valve, which is either functioning or not, mostly the function is vague. The pipe networks contain still other disturbance factors causing pressure variations, such as the pressure strokes especially in the daytime.

A significant disadvantage in the water pipe networks of the buildings is the fact that a relatively small leak has been difficult to observe at an early stage in a reliable and accurate way. The leaks are revealed only when the leak damages appear even years too late in the form of humidity damages, and they might have caused a lot of damage.

In addition to the pressure variations, the elasticity of the water pipe networks must be taken into account when evaluating the leak and its consequences. The elasticities of the pipe networks and of the different pipe materials are different, and the elasticity of the pipe materials is different in different temperatures. In particular, the great elasticity of

the plastic tubes causes problems in the measurings.

The aim of the invention is to bring about a method, by which an improvement is achieved compared with the present methods in observing the leaks in tap water systems and in the determinations of the size and quality of the leaks. In addition, the aim of the invention is to bring about a method, by which the leaks are determined more quickly and better than before and in a reliable way.

The aim of the invention is achieved by a method, which is characterized by what has been presented in the claims.

In a method in accordance with the invention, with the condition follow-up device continuous pressure balancing is performed with a pressure equalizer as well as pressure measuring for the whole pipe network with the network pressure in one measuring at desired intervals, such as favourably once in 24 hours, at such a time, as favourably in night-time, when the consumption is low and when there at the measuring moment is no consumption at all, however, only after the condition follow-up equipment has performed the preparatory basic functions. To the basic functions belongs that the pressure equalizer, which normally is in continuous operation, is separated from the network by a valve, whereat the valve concerned at the same time eliminates the impediments caused by the one-way valve and that by the valve, the tap water network is separated from the water distribution network. With the basic functions those disturbance factors are eliminated, which form an obstacle for a quick and reliable pressure measuring. The basic functions to be performed prior to the pressure measuring make an accurate and productive pressure measuring possible. This pressure measuring is performed at desired intervals, such as once in 24 hours or less frequently or more often depending on the object and the purpose. The pressure measuring is performed at such a time, when there is no consumtption in the pipe network. Under these circumstances it is generally most favourable to perform in the night-time, but depending on the object it can naturally be

performed at other times of the day as well. If the pressure does not go down during the measuring, there is no leak. In case the pressure goes down, the leak and its size are defined. The method in accordance with the invention makes a very accurate and productive pressure measuring possible.

In the condition follow-up equipment in accordance with the invention, the pressure variations are eliminated with a pressure equalizer, which is installed in the hot water network, where the pressure variations also come about. The pressure equalizer can be installed easily and simply in the already existing equipment or as a part of the industrially produced equipment entirety. The influence of the temperature/pressure variations is eliminated in an equipment in accordance with the invention favourably by the fact that the measuring is performed quickly in a few or perhaps twenty or thirty seconds and with the measuring accuracy of about 0.01 bar. By acting in such a manner the possible small variations in water temperature do not have the access to influence the measuring result.

In the equipment in accordance with the invention the influence of the one-way valve in accordance with the regulations, which is mounted between hot and cold water pipe networks, and which causes detrimental pressure relations between the networks, is eliminated by passing the valve during the test.

The changing in temperature is followed up in addition with a temperature sensing device also, which interrupts the measuring test in case the temperature tolerances are exceeded.

The measuring action is interrupted also then, if water consumption is observed in the water pipe network during the measuring time.

In addition to the pressure variations the elasticity of the water pipe networks plays a very big role in the evaluation of the sizes of the leak. This problem is removed in such a manner that before the installation of the condition follow-up equipment, the elasticity

of the network is measured and on the basis of this, the pressure measuring time is determined, which is needed for the defining of the size of the possible leak. Due to the different elasticities of the pipe networks the measuring time varies most commonly between about 4-10 seconds. On the basis of the measuring of the elasticity it is known, how much water is running out from the pipe network, when the pressure is going down for instance 1 bar (measuring accuracy of the pressure indicator being 0.01 bar). The elasticity test makes also the defining of the size of the leak possible. By comparing the different measurings it is possible to draw conclusions of the quality of the possible leak.

The elasticity is problematic in particular for the part of the plastic tubes due to their great elasticity, when the measuring time becomes longer. If there is air in the network, the elasticity grows. For this reason in the condition follow-up equipment in accordance with the invention, the pressure equalizer, if it is a membrane expansion tank, is separated from the network for the time of the measuring.

The condition follow-up equipment in accordance with the invention reveals whether the pipe network is leaking or not. In addition to this, the condition follow-up equipment reveals very small leaks, which just as hidden leaks cause irreplaceable damages. On the ground of physical measurings in practice, a leak of 1 1/24 hours can be observed in a 20 1 pipe network with a measuring time of about 5 seconds in a copper pipe network and in a plastic tube network with a measuring time of about 20-30 seconds.

The plastic tube network is very problematic due to its great elasticity. A small leak can be caused for instance by a tap packing. In practice a leak of 1 1/24 hours means the same as I drop of water every fourth second. The condition follow-up equipment is analyzing these small leaks by comparing the measurings between each other, whereat a packing leak or a toilet leak appear so that they are occasional, but a pipe leak is continuous.

The equipment implementing the method in accordance with the invention can be manufactured as an equipment entirety or it can be obtained from such maintenance

enterprises in the branch, which have acquired a portable condition follow-up device, in form of a measuring service, whereat the investment expenses are low. For new buildings it is most favourable to acquire an equipment entirety, which has the quality level of an industrial product.

In the following the invention is explained in more detail by referring to the attached drawing, in which figure 1 shows one application presented schematically of the equipment in accordance with the invention, figures 2 and 3 show the pressure variations of the hot water pipe network in a building before and after the installation of a pressure equalizer, and figure 4 shows the pressure change when a closed pipe network made of different materials is leaking (influence of elasticity).

The equipment presented in figure I is an integrated equipment entirety following the broken line, where the devices are installed in the pipe network in common. To it belong in this application the pipes 6, with the help of which the hot water pipe network 1 and the cold water network 2 are connected to the income water pipe network 5 as well as the pressure equalizer 3, the valves, such as the decompression valve 17, the pressure relief valve 23, the three-way valves 19 and 22, regulator valve 20, two ball barrage valves 21 for the pressure indicators, the one-way valve 4 and other necessary shut-off valves 7, the pressure indicator 8, and pressure sensor/pressure indicator 8a, temperature sensor/thermometer 9 and backwater pump 10. The pressure equalizer 3 is in this application a membrane pressure equalizer. The pressure equalizer is placed in the hot water pipe network and it is on the hot water side from the one-way valve 4. The pressure equalizer 3 is coupled to the hot water network through the three-way valve Mv 22. The pressure equalizer 3 can be separated from the net with the three-way valve Mv 22 and at the same time the operation of the one-way valve can be closed with the help of the bypass pipe 34. To the equipment can naturally belong also other as such known,

in this kind of equipment usable valves, filters, meters or other similar devices or organs, the number of which cannot be limited in any way. In the income water network there is the one-way valve 12, which is a combined shut-off and one-way valve. To the pressure measuring operation belong the solenoid valve 31, the pressure transmitter 8a and temperature transmitter 9, the piping 32, and they are installed in the equipment entirety in the way presented in figure 1. The sub-centre 30 is installed outside the main equipment, but it belongs to the equipment entirety. The piping 33 to the control centre does not belong to the equipment entirety. The equipment is connected in this application as an integrated entirety on its spot on the frame or corresponding. The piping 11 of the boiler is connected to the equipment.

In figures 2 and 3 the pressure variations of a building are presented before and after the installation of a pressure equalizer. As from the figure 2 can be seen, the pressure variations are relatively great even in ordinary use. In the building a pressure equalizer was installed in the way figure I shows for balancing of the hot water pressure variations.

In the following measurings the values according to figure 3 for the pressure variations were achieved. With the pressure equalizer the pressure was balanced efficiently.

In figure 4 pressure variations are presented when a closed network made of different pipe materials is leaking. From the figure appears quite clearly the dominating effect of the elasticity.

The invention is not limited to the presented favourable application, but it can vary within the limits of the inventional idea determined by the claims.