Correction Factor Owing To Use Of Glycol (Only For Hi-Therma Monobloc) - Hisense Hi-Therma Series Service Handbook

3.3.2 Correction factor owing to use of glycol (only for Hi-Therma Monobloc)

Application at low ambient temperature
When the ambient temperature is low in winter, the water in the pipes and circulating pump may freeze and damage the pipes
and water pumps during shutdown periods.
To prevent this, it is useful to drain the water from the installation or not to cut off the power supply of the installation,
anti-freezing function will be triggered to prevent freezing.
In addition, in cases where it is difficult to drain the water, it is advisable to use a mixture with antifreeze glycol (ethylene or
propylene at a concentration between 10% and 35%).
When glycol is added to the system, the performance of the unit will be affected. The correction factor of the unit capacity,
flow rate and pressure drop of the system is listed in the tables below.
-Ethylene glycol
Concentration of
ethylene glycol
Capacity
(%)
0 1.000
10 1.000
20 1.000
30 0.990
35 0.990
-Propylene glycol
Concentration of
propylene glycol
Capacity
(%)
0 1.000
10 1.000
20 1.000
30 0.990
35 0.990
Uninhibited glycol will turn acidic under the influence of oxygen. This process is accelerated by presence of copper and
at higher temperatures. The acidic uninhibited glycol attacks metal surfaces and forms galvanic corrosion cells that cause
severe damage to the system. It is of extreme importance:
- That the water treatment is correctly executed by a qualified water specialist.
- That a glycol with corrosion inhibitors is selected to counteract acids formed by the oxidation of glycols.
- That in case of an installation with a domestic hot water tank, only the use of propylene glycol is allowed. In other
installations the use of ethylene glycol is fine.
- That no automotive glycol is used because their corrosion inhibitors have a limited lifetime and contain silicates that can
foul or plug the system;
- That galvanized piping is not used in glycol systems since it may lead to the precipitation of certain elements in the
glycol's corrosion inhibitor;
- To ensure that the glycol is compatible with the materials used in the system.
The use of glycol affects to the reading of some parameters like "water flow level" and "capacity" shown through the unit
controller menu. When glycol is used, these data are not correct and must be not used.
Modification coefficient
Power input Water flow
1.000 1.000
0.998 1.010
0.995 1.010
0.992 1.020
0.991 1.030
Modification coefficient
Power input Water flow
1.000 1.000
0.996 1.020
0.992 1.020
0.988 1.040
0.986 1.050
31
Capacity and selection data
Freezing point (°C)
Water resistance
1.000
1.030
1.090
1.160
1.210
Freezing point (°C)
Water resistance
1.000
1.240
1.310
1.390
1.450
0
-4
-9
-16
-20
0
-3
-7
-13
-18