22
Installation instructions
3.11 - FILLING THE SYSTEM
Attention!
Do not mix the heating water with incorrect
concentrations of antifreeze or anti-corrosion
substances! This could damage the gaskets
and cause noise during operation.
Unical will not be held liable for damage to
persons, animals or objects due to failure to
comply with the instruction above.
After completion of all the hydraulic connections, fill the
boiler and proceed with the inspection of soundness of all
the connections.
This operation must be performed carefully, respecting the
following phases:
- open the radiator air release valves;
- open the filling tap gradually, making sure that the automatic
air release valves installed on the system work properly;
- close the radiator air release valves as soon as water comes
out;
- check the pressure gauge until pressure reaches
approximately 1 bar (this is valid only for installations equipped
with a closed expansion vessel - consult local regulations
if this is allowed); for installations equipped with an open
expansion vessel, restoration is carried out automatically
via the same expansion vessel;
- close the filling tap of the system and bleed air once again
through the radiator air release valves;
- make sure that all the connections are watertight;
- after commissioning the boiler and bringing the system to
the operating temperature, stop the pumps and repeat the
air bleed operations;
- let the system cool down and, if necessary, bring the water
pressure back to 1 bar (this is valid only for installations equip-
ped with a closed expansion vessel - consult local regulations
if this is allowed); for installations equipped with an open
expansion vessel, restoration is carried out automatically
via the same expansion vessel;
NOTE
In systems equipped with closed expansion vessel,
where allowed, the water pressure in the heating
system - with the system cold - must not drop below
1 bar; open the filling tap when pressure is too low.
This operation must be performed with the system
cool.
The pressure gauge fitted on the system allows
you to read circuit pressure.
NOTE
If the boiler was without electric power, after a
certain idle period, the pump could be blocked.
Before turning on the main switch, the pump must
be unblocked by operating as follows:
Introduce a screwdriver in the hole below the
protective screw in the centre of the pump intended
for this purpose and turn the pump shaft clockwise.
After having unblocked the pump, tighten the
protective screw and make sure there is no water
leakage.
ATTENTION!
After removing the protective screw, a small
amount of water could leak out. Dry off all wet
surfaces before powering the boiler.
fig. 21