mundoclima AEROTHERM MAM-V9 Serie Manual De Usuario E Instalacion página 130

9.4.4 Water circuit anti-freeze protection
Ice formation can cause damage to the hydraulic system. As the outdoor unit may be exposed to sub-zero temperatures, care
must be taken to prevent freezing of the system.
All internal hydronic parts are insulated to reduce heat loss. Insulation must also be added to the field piping.
The software contains special functions using the heat pump to protect the entire system against freezing. When the
temperature of the water flow in the system drops to a certain value, the unit will heat the water, either using the heat pump,
the electric heating tap, or the backup heater. The freeze protection function will turn off only when the temperature
increases to a certain value.
In event of a power failure, the above features would not protect the unit from freezing.
Since a power failure could happen when the unit is unattended,the supplier recommends use anti-freeze fluid to the water
system. Refer to "Caution: Use of glycol" .
Depending on the expected lowest outdoor temperature, make sure the water system is filled with a concentration of glycol as
mentioned in the table below.
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 table below.
Ethylene Glycol
Quality of
Cooling capacity
glycol/%
modification
0 1.000
10 0.984
20 0.973
30 0.965
40 0.960
50 0.950
Propylene Glycol
Quality of
Cooling capacity
glycol/%
modification
0 1.000
10 0.976
20 0.961
30 0.948
40 0.938
50 0.925
If no glycol is added, the water must be drained out when there is a power failure.
Water may enter into the flow switch and cannot be drained out and may freeze when the temperature is low enough. The flow
switch should be removed and dried, then can be reinstalled in the unit.
Ethylene Glycol and Propylene Glycol are TOXIC
The concentrations mentioned in the table above will not prevent freezing, but will prevent the hydraulics from bursting.
Modification coefficient
Power Water
modification resistance
1.000 1.000
0.998 1.118
0.995 1.268
0.992 1.482
0.989 1.791
0.983 2.100
Modification coefficient
Power Water
modification resistance
1.000 1.000
0.996 1.071
0.992 1.189
0.988 1.380
0.984 1.728
0.975 2.150
WARNING
127
Freezing
Water flow
point/
modification
1.000 0.000
1.019 -4.000
1.051 -9.000
1.092 -16.000
1.145 -23.000
1.200 -37.000
Freezing
Water flow
point/
modification
1.000 0.000
1.000 -3.000
1.016 -7.000
1.034 -13.000
1.078 -22.000
1.125 -35.000