A.O. Smith 30 - Manual (Page 19)

Instruction manual SGS 19
gis
2.7 Safety of the solar
heating system
2.7.1 Expansion vessel
The solar heating system must be equipped with an expansion vessel (16). An
expansion vessel serves to limit pressure variations in the system. The
expansion vessel in the solar heating system can withstand a maximum
pressure of 6 bar. The supply pressure to the expansion vessel depends on the
static head of the system.
Besides the expansion vessel, the system is protected from overpressure by an
expansion valve
(2.7.2 "Expansion valve") .
2.7.2 Expansion valve
The solar heating system is equipped with an expansion valve (23). The
expansion valve monitors the pressure in the solar heating system. If the
pressure is excessive (> 6 bar), then the valve will open. The hot water can now
flow out of the installation. The valve remains open until the unsafe situation has
passed, i.e. until the pressure has fallen back below 6 bar.
Note
Because the installation is always under pressure and is not automatically
filled, the system will again need to be replenished (5 "Filling") .