Free-Cooling - Lennox CLIMATIC 50 User Manual

FREE-COOLING

Function
Ensure optimum cooling capacity though the use of free cooling, therefore reducing electrical consumption.
Description
$ Free-cooling principle
3 Way
Eva
TEE % Chilled Water Inlet temperature (°C)
TSE % Chilled Water Outlet temperature (°C)
TEA % Outdoor air temperature (°C)
$ Control of the free-cooling 3 way valve
3 way valve is activated if the following conditions are met.
" The free cooling function on the Chiller is activated by switching the menu 3843 to "ON"
" The unit is running
" Ambient air temperature (TEA) is below the set leaving chilled water set point minus 3°C
" Chilled water circulation pump has been running for at least 30 seconds
$ Control of the free-cooling fans
In the case where the free cooling fans are the same as the main refrigeration circuit fans, (which is the most
common case for Lennox units), they are constantly running if the compressors are stopped and if the chilled
water outlet temperature is above the set point defined in menu 3321 and 3322.
When a compressor starts, the fans run as without free-cooling.
In the case where the fans of one circuit are running full speed for at least 3 minutes, the cooling by free
cooling only is not sufficient to reach the chilled water set point, the control allows the compressors of that
circuit to start.
In the case where the free cooling circuit is independent from the main refrigeration circuit (separate fans
and coils), the free cooling fans are allowed to run for as long as the chilled water outlet temperature has not
reached the set point defined in menu 3321 and 3322.
$ Compressor Operation
For the compressor control, if the outside temperature is lower than the chilled water inlet temperature, the
free-cooling is considered as an additional first compressor stage by the control.
CLIMATIC 50, user manual – Chillers ranges
TEE
FANS
TEA
Free cooling coil
TSE
CL50-CHILLERS/IOM/0906-E
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