INSTALLER
35
r g
boilers must be fitted with a central hea-
ting circuit filling system connected to the boiler return
line.
FILLING THE SYSTEM
- Make sure that the central heating drain cock (1)
and storage cylinder drain cock (2) (
NK
models) are
closed before you start filling the system.
- Open the non-return valve (3) to facilitate filling (the
slot in the screw must be perpendicular to the direc-
tion of flow).
- Open the shut-off cocks for the water circuit.
- Slowly fill the system to a cold pressure of
1.5 bar
.
- Close all previously opened valves including the
non-return valve (3) (
NK
models) (the slot in the
screw must be parallel to the direction of flow).
NOTE
The system is de-aerated automatically through the
automatic vent valve (4) (
NK
models).
1
g
N
4
3
2
open
closed
1
g
60 NK
4
3
2
1
aperta
chiusa
g
100 NK
FILLING AND EMPTYING THE SYSTEM
