Technical data

To facilitate the operation of bleeding air from the hydraulic circuit, the appliance is

equipped with an additional manual air bleeding valve.

Use of glycol antifreeze

Glycols, normally used to lower the freezing point of water, are substances in an inter-

mediate state of oxidation which, in the presence of oxidising agents such as oxygen,

are transformed into corresponding acids. This transformation into acids increases the

corrosive nature of the ﬂuid contained in the circuit. For this reason, mixtures that are

commercially available almost always contain inhibiting substances that are able to con-

trol the pH of the solution. A condition necessary for the oxidation and degradation of

glycol is the presence of an oxidising agent such as oxygen. In closed circuits in which no

replenishment of water (and therefore of oxygen) occurs over time, once the oxygen ini-

tially present has reacted, the degenerative phenomenon of glycol is hugely inhibited.

Most circuits, however, are of the non-sealed type, and therefore receive a more or less

continuous supply of oxygen.

Therefore it is essential, whatever type of glycol is in question, to verify that it is ade-

quately inhibited and that the necessary checks are regularly performed during its entire

period of use.

Antifreeze liquids for cars, which do not contain inhibiting components other than ethyl-

ene glycol, are not recommended for cooling and heating plants.

The manufacturer does not accept any contractual or extra-contractual liability for

damages caused by the use or disposal of glycol antifreeze.

It is equally important to recall that the use of monoethylene glycol modiﬁes the ther-

mophysical characteristics of the water in the plant, and in particular its density, viscosity

and average speciﬁc heat. Always check the date of expiry and/or degradation of the

product with the supplier.

The technical data (Tables 3.1 GS HT/LT technical data → 12 and 3.2 WS technical da-

ta → 13) regarding the hot circuit refer to non-glycolised water, so that the correction

factors of Table 5.3 Technical data for ﬁlling the hydraulic circuit → 36 must be applied

to obtain the consequent increased load drop of the system and penalisation of unit ef-

ﬁciency in relation to the percentage of monoethylene glycol used.

Table 5.3 Technical data for ﬁlling the hydraulic circuit → 36 should be taken into account

for the sizing of the pipes and the circulation pump (for calculation of internal pressure

drops of the appliance, refer to Tables 3.1 GS HT/LT technical data → 12 and 3.2 WS tech-

nical data → 13).

Nevertheless, it is advisable to consult the technical speciﬁcations of the monoethylene

glycol used. If automatic loading systems are used, a seasonal check of the quantity of

glycol present in the plant is also necessary.

Table 5.3 – Technical data for ﬁlling the hydraulic circuit

% of MONOETHYLENE GLYCOL 10 15 20 25 30 35 40

WATER-GLYCOL MIXTURE FREEZING TEMPERATURE -3°C -5°C -8°C -12°C -15°C -20°C -25°C

PERCENTAGE OF INCREASE IN PRESSURE DROPS -- 6% 8% 10% 12% 14% 16%

LOSS OF EFFICIENCY OF UNIT -- 0,5% 1% 2% 2,5% 3% 4%

If the percentage of glycol is ≥ 30% (for ethylene glycol) or ≥ 20% (for propylene glycol):

then parameter 182 in menu 4 must be set to “1” (at the installer’s care).•