EN
5
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.
The open-circuit gravity system requires the installation of a non-return valve in order
to prevent the water from draining out of the tank in the event of the water supply
running dry or being shut down. This installation mode requires the use of a cross-
flow mixer 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.
The closed-circuit pressure system requires the use of pressure mixer taps. For
safety reasons the supply pipe must be fitted with a safety valve or alternatively, a
valve of the safety class that prevents the pressure in the tank from exceeding the
nominal pressure by more than 0.1 MPa (1 bar). The outlet opening on the relief
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.
In case the existing plumbing does not enable you to pipe the dripping water from the
safety valve into the drain, you can avoid the dripping by installing a 3-litre expansion
tank on the inlet water pipe of the boiler.
In order to provide correct operation of the safety valve, periodical inspections of the
relief valve must be carried out by the user to eliminate any limescale and check if the
safety valve is 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.
