26
EN
CONNECTION TO WATER SUPPLY MAINS
Water inlet and outlet on the heat pump are marked with colours. Cold water inlet is
marked with blue, and warm water outlet is marked with red. The heat pump is
designed for connection to indoor water supply mains without using the relief valve if
the pressure in the supply mains is lower than 1.0 MPa (10 bar). If the pressure is
higher, a relief valve needs to be installed so as to provide that the pressure at the
inlet to the hot water tank does not exceed the nominal pressure.
Installing a safety valve is mandatory in order to assure safe operation. The valve
prevents an increase of the pressure in the boiler by any more than 0.1 MPa (1 bar)
above the rated pressure. The outflow nozzle on the safety valve must have an outlet
into the atmosphere. To assure correct operation of the safety valve, the valve must
be regularly checked.
When checking the valve, push the lever or unscrew the nut of the valve (depending
on the type of the valve) and open the drain from the safety valve. Water must flow
from the valve nozzle, showing that the valve operation is faultless. During the
heating of water, the water pressure in the hot water tank is increased up to the level
preset in the safety valve. Since the system prevents backflow of water into the water
supply mains, water may be dripping from the outlet opening on the safety valve. The
dripping water may be drained via trap into the drains; the trap is mounted under the
safety valve. The outlet pipe, which is mounted under the safety valve, must be
directed downwards, in a place with a temperature above freezing.
If the installation does not allow draining of the water from the safety valve into the
drains, dripping can be avoided by installing an expansion vessel onto the heat pump
inlet pipe. The volume of the expansion vessel must be ca. 3% of the hot water tank
volume.
Fig. 6: Closed (pressure) system
Legend:
1 - Pressure mixer taps
2 - Expansion tank
3 - Safety valve
a - Test valve
b - Non-return valve
4 - Funnel with outlet connection
5 - Checking fitting
6 - Pressure reduction valve
7 - Closing valve
H - Cold water
T - Hot water
