48
EN
3 INITIAL START-UP
3.1
System filling
3.1.1
Cleaning the solar circuit
Two cocks are used for cleaning and filling the circuit: one for
filling and the other for discharging, separated by a shut-off
valve. For improved operation, the cocks contained in the solar
unit should be positioned in the lowest point of the system. A
third cock could be inserted in the lowest point of the system,
for draining the system completely.
Before the system is filled with the water-anti-freeze liquid
mixture, it must be rinsed out by letting water flow through it.
This will help to expel any processing residues from the solar
circuit.
– Open the cock (A) and connect it with a rubber pipe to the cold
water cock.
– Open the cock (B) and connect it with a rubber pipe to the
water drainage outlet.
– Close the shut-off valve (V).
– Close all the shut-off cocks before the automatic relief valves
or all the manual relief valves.
– Open the water tap and allow water to flow vigorously through
the solar circuit for a few minutes.
– If this operation is carried out when there is a risk of frosting,
be very careful when emptying the collector the next time to
avoid ice build-up which could cause the panel to break.
FILLING
DISCHARGE
Fig. 22
If the collectors are not operated for extended periods of time,
we suggest disconnecting them from the rest of the system, so
that air can flow freely inside the system, and covering them
with a shade cloth for vegetable gardens so that they do not
overheat excessively.
3.1.2
Checking tightness
End the rinsing phase by closing cock (B) and raise the pres-
sure inside the solar circuit until it reaches 0.2 bar less than the
calibration value of the safety valve (for example, 6 bar for the
safety valve, try adjusting it to 5.8 bar).
– Close cock (A) and then also close the water tap.
– Open the shut-off cock (V).
– On the control unit set manual operation for the solar circuit
pump, open the shut-off cocks of the relief valves and bleed
the air from the solar circuit, by also intervening manually:
– on the roof, by removing the plug from the relief valve
and applying pressure with the tip of a screwdriver;
– on the central heating device, through the degasser
contained in the solar unit.
– Check the pressure again and restore its value (if necessary)
by opening cock (A) and the water tap.
– Visually inspect all the pipes and couplings carefully for any
losses and leave the system pressurised for a few hours to
verify whether any pressure losses occur.
The system can be operated for a while in trial mode only with
the recirculation water to adequately verify whether there are
any leakages, if there is no risk of frosting.
a
WARNING
If often happens that new systems freeze up because
the owner purchase the anti-freeze liquid but failed
to insert it in the system. To avoid similar problems,
make sure you add the anti-freeze liquid.
3.1.3
Emptying the solar circuit
Connect both cocks with rubber pipes to a bucket to drain and
empty the system. The amount of water can be measured and
used for preparing the water and glycol mixture. To empty the
system, the relief valves must be kept open to allow air into the
system, by applying pressure with a screwdriver, if necessary,
to facilitate the operation.
a
WARNING
All the water inserted in the circuit must have been
drained to prevent it from freezing and damaging the
panel.
3.1.4
Filling the solar circuit
Before filling the circuit, it is necessary to check the expansion
vessel’s pre-charge pressure using a pressure gauge or a bi-
cycle pump; it must be roughly 0.3 bar lower than the system’s
cold charge pressure.
If anti-freeze liquid will be used, the water and glycol must be
mixed in a container before they are poured into the system.
The percentage of glycol depends on the minimum tempera-
ture that can be reached in the area where the system will be
installed (the data can be inferred from the historical tables of
the zone’s minimum temperatures). This temperature must be
reduced by at least another 10°C because the panel can cool by
roughly 6–7°C more than the outdoor temperature.
To be on the safe side, add the anti-freeze liquid until it reaches
40% of the total mixture (no less, regardless of the degree of
protection, so as to have an effective anti-corrosion action on
the pipes).
a
WARNING
Any breakages due to ice are not covered by warranty.
