The highest operating pressure allowed for the tank.
This parameter must not be lower than the constant operating pressure in the heating/water supply system. However, the specific values depend on the type of system and the type of tank (see above). So, for a water pressure tank, the maximum operating pressure must be higher than the shutdown pressure of the pump. In general, rather high-pressure values are found in water supply systems, so most modern water pressure tanks fall into one of the following categories:
6 bar,
8 bar,
10 bar and
more than 10 bar(although there are models with more modest values).
In turn, the expansion tank must withstand the pressure at which the safety valve in the heating system is activated. Most of these tanks are designed for
3 bar,
4 bar or
5 bar — heating systems rarely use higher pressures (although exceptions are possible here).
In general, when choosing this parameter, the rule “the more the better” works quite well: a good pressure margin will provide an additional guarantee in case of emergencies. The reverse side of this reliability can only be called a slightly increased price.
