9
Filling the circuit
FILLING THE CIRCUIT
Perform the following steps before starting up the system.
1 - FLUSHING AND SEAL TESTING THE SYSTEM
If copper piping has been used and joints have been hot
brazed, flush out the system to remove any brazing resi-
dues. Seal test the system after you have flushed it out.
b
Fill the solar collector with glycol/water mix immedi-
ately after flushing it out, because flushing water may
remain trapped in the circuit (with a consequent risk
of freezing).
2 - PREMIXING WATER + GLYCOL
Glycol anti-freeze is supplied separately in standard vol-
umes and must be premixed with water in a suitable con-
tainer before being used to fill the system. For example,
a mix of 40% glycol and 60% water provides anti-freeze
protection down to a temperature of -21°C.
b
The propylene glycol supplied is specially formulat-
ed for solar collector applications and remains fully
efficient throughout the -32 to +180°C temperature
range. It is also non-toxic, biodegradable and bio-
compatible.
b
Do NOT part fill the circuit with pure glycol then add
water later.
3 - FILLING
b
Only fill and bleed the solar circuit at ambient temper-
ature, with the collectors shielded from the sun’s rays.
1 Open the non-return valve (A)
2 Open the air vent at the highest point in the system (see
figure alongside) and keep it open throughout the filling
operation
3 Open the vent valve (7)
4 Pump the heat transfer fluid around the circuit with an
external filling pump until all air bubbles have been
eliminated. Close the manual bleed valve
5 Temporarily raise the pressure in the system to 4 bar
6 Start up the system for about 20 minutes
7 Bleed the circuit again from step 2 until all the air has
been removed
8 Set the circuit pressure according to the table on the
next page in order to ensure a minimum pressure of 1.5
bar at the height of the collector field
9 Close the non-return valve (A) and any open vent valves
to prevent the heat transfer fluid from evaporating.
b
Make sure that you have bled all the air out of the sys-
tem, using the water control system vent too.
Heat transfer fluid filling pump (accessory). A manual
bleed valve is not required if this pump is used.
Anti-freeze
Temperature
Density
50%
-32 °C
1,045 kg/dm
3
40%
-21 °C
1,037 kg/dm
3
30%
-13 °C
1,029 kg/dm
3
A
R
M
7
Anti-freeze mix
Water control system
Heat
transfer fluid
filling pump
Solar collector
Manual
bleed valve
(accessory)
Heat exchanger
of solar
°C
M
T
