3 Capacity and selection data
Correction factors
TCGB0123 rev.2 - 10/2019
66
3.4.2 Correction factor owing to use of glycol (only for YUTAKI M)
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, as
an electrical cable can prevent the water from freezing in the circuit.
In addition, in cases where it is difcult to drain the water, it is advisable to use a mixture with antifreeze glycol (ethylene
or propylene at a concentration between 10% and 40%).
Unit performance may be reduced when operating with glycol, depending on the percentage of glycol used, since glycol
is denser than water.
Two tables are shown below (one for ethylene glycol and the other for propylene glycol), indicating the percentage of
ethylene glycol recommended for diverse values of outdoor air inlet temperature, with their respective correction factors.
Corrected heating capacity = capacity correction factor owing to use of glycol × heating capacity
- Ethylene glycol
Ambient Temperature DB (°C) -3 -7 -13 -22
Percentage of glycol required % 10 20 30 40
Capacity correction factor
f
gh
1.00 1.00 0.99 0.99
Consumed power correction factor
f
gi
1.01 1.02 1.03 1.04
Flow rate correction factor
f
gc
1.01 1.01 1.02 1.04
Pressure loss correction factor
f
gp
1.03 1.09 1.16 1.26
- Propylene glycol
Ambient Temperature DB (°C) -3 -7 -13 -22
Percentage of glycol required % 10 20 30 40
Capacity correction factor
f
gh
1.00 1.00 0.99 0.99
Consumed power correction factor
f
gi
1.01 1.02 1.03 1.04
Flow rate correction factor
f
gc
1.02 1.02 1.04 1.07
Pressure loss correction factor
f
gp
1.24 1.31 1.39 1.51
! CAUTION
The use of glycol affect to the reading of some parameters like “water ow level” and “capacity” shown through the unit controller
menu. When glycol is used, these data are not correct and must be not used.
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