46
English 05/09
ACCURATE AX - AW - AD - AT - AF
CALIBRATING THE THERMOSTATIC VALVE
(air-cooled models)
The thermostatic valve is calibrated using the adjustment screw
shown in the figure; in the water-cooled models, the correct cali-
bration is already performed in the factory.
• Check that the subcooling of the liquid at the condenser outlet
is around 3-5°C;
• Check that the thermostatic valve superheating value is cor-
rect (around 5 °C);
• Check that the valve sensor bulb is correctly positioned,
secured and insulated.
If the superheating is above the value indicated previously, open
the valve further; if it is lower, close the valve further.
NOTE:
the thermostatic valve must only be calibrated by
specialist personne
OPERATION AND CONTROL
A
I
U
WATER-COOLED UNITS
Water in an open circuit
If the temperature of the cooling water is not controlled and may fall
below 25°C, a pressure control valve is required (available as an
accessory) for each condenser; in this case, the supply pressure must
not be less than 200 kPa (2 bar).
IMPORTANT: do not use water cooled using an evaporative tower, as
the condensers will rapidly become fouled by lime scale.
Water in a closed circuit
The condensers on the units are supplied with water pumped in a
closed circuit and cooled by external radiators; check that the cross-
section of the pipes and that the characteristics of the circulating
pump are suitable: an insufficient water flow-rate affects the perfor-
mance of the air-conditioner. The temperature of the cooling water
must be controlled so as to not fall below 25°C, preferably according
to the diagram shown in the figure.
IMPORTANT:
the cooling water must contain a percentage of
ethylene glycol (passivated and consequently non-corrosive)
according to the minimum expected outside temperature.
In the Energy Saving models, the use of glycol is always required.
B
C
A
25 °C
adjustment screw
