5
EN
CONNECTION TO THE WATER SUPPLY
The water heater connections for the inlet and outlet of water are colour-coded. The
inlet of cold water is marked with blue colour, while the hot water outlet is marked
with red colour.
The water heater can be connected to the water supply in two ways. The closed-
circuit pressure system enables several points of use, while the open-circuit gravity
system enables a single point of use only. The mixer taps must also be installed in
accordance with the selected installation mode.
In a closed, pressurized system pressurised mix taps should be used at the outlet
points. To ensure safe operation of the heater a safety valve should be installed on
the inlet pipe to prevent elevation of pressure for more than 0.1 MPa (1 bar) above
the nominal pressure. The outlet opening on the safety valve must be equipped with
an outlet for atmospheric pressure. The heating of water in the heater causes the
pressure in the tank to increase to the level set by the safety valve. As the water
cannot return to the water supply system, this can result in dripping from the outlet of
the safety valve. The drip can be piped to the drain by installing a catching unit just
below the safety valve. The drain installed below the safety valve outlet must be
piped down vertically and placed in an environment that is free from the onset of
freezing conditions.
To avoid water dripping from the safety valve, an expansion tank should be installed
on the inlet pipe of the heater with the capacity of at least 5 % of the heater volume.
To ensure proper operation of the safety valve, periodical inspections must be carried
out to remove limescale and make sure the safety valve is not blocked.
To check the valve, open the outlet of the safety valve by turning the handle or
unscrewing the nut of the valve (depending on the type of the valve). The valve is
operating properly if the water comes out of the nozzle when the outlet is open.
An open-circuit, non-pressurised system requires the installation of a non-return valve
at the water inlet to prevent water draining out from the tank in the event of the water
supply running dry. This installation mode requires the use of an instantaneous
mixing tap.
As the heating of water expands its volume, this causes the tap to drip. The dripping
cannot be stopped by tightening it further; on the contrary, the tightening can only
damage the tap.
