Control System; Cwp Control System Μchiller; Temperature Controller - Johnson Controls CWP Manual De Instalación Y Mantenimiento

Control System

6 CONTROL SYSTEM
6.1 CWP
Control system

6.1.1 Temperature controller

The controller mounted on COOLING ONLY units is
shop calibrated to control the unit according to the
temperature of the chilled water returning from the
system. Therefore, its probe is installed in the point
where the water enters the refrigerant/water ex-
changer, so that it can detect the system load. The
only regulation required for the controller is the cali-
bration of the set point, which can be carried out in
the 10 to 18 °C range (the shop calibration is 12
°C). Regarding the units in HEAT PUMP solution, the
controller can be calibrated from 25 °C to 45 °C for
heating (the shop calibration is 40 °C); the require-
ments specified for the units in cooling only solution
shall apply also to cooling.
Interfacing panel of the control system controller
Comp
x 100
Page 16
µchiller
PRG
Mute
SEL
In order to set the cooling set point to a value lower
than the shop setting, it is essential that you add
some antifreeze to the circulating water and re-cali-
brate accordingly all the safety components of the
equipment.
N : To set the entering water temperature set
OTE
point to values below 10 °C, consult our Technical
Department to become acquainted with all the pre-
cautions that should be adopted for a perfect oper-
ation of the equipment
6.1.2 Antifreeze function
The antifreeze protection (managed by the con-
troller) is activated on all models when the leaving
water temperature drops to a value below 4 °C, and
causes the safety stop of the unit. This safety device is
a complement to the differential safety pressure
switch.
Clear