Safety valve and assembly onto the water heater

The valve for the water heater is a fundamental device for this type of application as it allows to reduce waste but, above all, it guarantees a high level of safety both for the systems and for the people who are in the vicinity. It therefore appears evident that it does not only represent an important aspect such as the design and construction according to regulations of this type of components, but it is also a necessity.

In particular, this type of valve allows to obtain two functions at the same time:
-    Safety: it is obtained by means of a spring that acts on a shutter. If the detected pressure value of the fluid exceeds the maximum allowable calibration value (typically 8 bar), the shutter is opened and allows a discharge with liquid leakage until an allowable pressure value is reached;
-    Retention: it is obtained by means of a gasket and a patented "anti-drip" system that allows you to avoid unpleasant leaks and drips that reduce the efficiency of the system and compromise its ideal operation.
Another important feature that can be found is that the valves can have manual or automatic emptying. In the first case there is a lever that can be operated manually by an operator without having to disassemble the valve itself, while in the second case there is no such lever. In any case, regardless of the possibility of manual action, they are designed so that a modification of the “factory” setting of the component cannot be carried out by personnel not authorized to perform this function.

The valves present in the dedicated section of the Gnali Bocia catalog have common constituent elements:
-    Body: made of EN 12165- CW617 N brass, it constitutes the external body of the valve;
-    Springs: made of stainless steel, they perform the function described above in conjunction with the shutter;
-    Gasket: made of "anti-sticking" synthetic rubber, it guarantees the seal of the component avoiding leaks or malfunctions that can damage the efficiency and performance of the entire system.
These are the main components, although there are other details always made of brass or with the use of heat-resistant plastic materials.

Other important aspects concerning this type of components, as for all devices that carry gaseous or liquid fluids, are the maximum allowable values of pressure and temperature. As regards the latter, the maximum permissible operating temperature is approximately 100 ° C; on the other hand, as regards the calibration pressure, the standard value is equal to 8 bar, even if other calibrations can be made on customer request.

The valves for the water heater, as previously mentioned, are an essential component within these systems as they allow to perform functions both from the point of view of safety and from the point of view of the direction of the fluid, blocking the opposite direction and not allowing reflux which is an important problem.
For this reason, the role of the installer and maintenance technician is essential to avoid breakages and malfunctions that can lead to sudden or prolonged failures over time, causing various kinds of inconvenience to both persons and the buildings where the water heaters are located.

Although it is a relatively simple component both in terms of architecture and function (simple but, as seen, very important!), The installation of the safety valves inside the water heaters presents a series of difficulties which, if underestimated, can totally compromise the application of these devices. In fact, both from the regulatory point of view and from the point of view of common sense, it must be carried out by a qualified and experienced technician.
The first step is to secure the valve to the flexible pipe that serves to supply the system. Subsequently, the water drain hose is loaded which is used to drain the fluid after passing through the water heater. Finally, to verify that there are no leaks or other problems, we proceed to the testing phase. Only at this point the system is ready for operation and can be switched on.

The installer, after the implementation phases, also takes care of the adjustment and calibration of the valve following:
- Technical data sheet: it is characteristic of each valve and presents the basic conditions for correct operation both in terms of pressures and temperatures;
- Regulations: every country in the world, in fact, has specific regulations regarding safety valves, even if continental or world standards can be followed.
Once these aspects have been verified, the technician proceeds to the pressure calibration phase and monitors correct operation in the initial phases.

If a breakdown occurs, it is mandatory to contact highly specialized personnel again to avoid safety problems and / or cause further damage to the system with the related economic consequences. The operator, having verified the fault and sensing the problem, proceeds to turn it off and replace the valve with a corresponding one, carrying out the previously presented steps again.
In general, what emerges from this analysis is that being central and critical components, they require attention and study before proceeding with any operation both during assembly and disassembly.

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