Unit installation

55
MOP management
MOP is the maximum allowed value of SP: if SP > M82 the control algorithm is bypassed and the Electronic
Expansion Valve should be closed to reach the MOP value:
SP < MOP: PI control is enabled
MOP< SP < MOP + 5 PSI: the control output is locked
SP > MOP + 5: the control output decrease of 0.5%
Pulsed Hot Gas Bypass Solenoids
The Hot Gas Bypass Solenoid will be managed in pulsed mode, if setup parameter M60 <> 0 and the Unloading
are enabled without HGBS (M21=2).
The following assumptions are made:
• Setup parameter M60 is the switching time, in seconds, of HGBS.
• In every board (Master or Slave) the HGBS valve will work in pulsed mode, if at least one compressor is
switched on.
• When the pulsed mode is enabled, in the first M60 seconds, the HGBS will be switched off.
• If both compressors of the single boards are switched off, the HGBS will be switched off.
Two Barrels management
The selection of one barrel or two barrels management is made by M16 installer setup parameter:
M16 = 0 select one barrels management;
M16 = 1 select two barrels management.
If two barrels management is enabling then the following assumptions are made:
• Evaporation temperature on the first barrel (EV1BT) is read by the TOUT probe of CP3-4 board.
• Evaporation temperature on the second barrel (EV2BT) is read by the TIN probe of CP3-4 board.
• Anti freeze alarm is checked on the temperature LWT, RWT, EV1BT, EV2BT.
LCD DATA DISPLAY
In the normal operating mode the 20 x 4 LCD displays the system status, the IN and OUT temperatures, the set
point, run time of the chiller, the alarm history (e.g. list of the last 9 alarms). In addition, for each circuit:
• Suction and discharge pressure
• Compressor status
• Fan status
• Liquid line solenoid status
• Run time of compressor
The control temperature (Tc) is continuously displayed on the 3 digit LED display.
In the normal operating mode the 20X4 LCD displays:
COOLINE
AIR CONDITIONERS
LWT 24.5 RWT 31.5 °F
SP 23.5°F Cooling 100% SP 23.5°F SYSTEM OFF
LWT : Leaving water temperature
RWT : Return water temperature
SP : Set point
% : Denotes the current % cooling demand
If UP key is pressed we show other information about the chiller
T CONTROL LWT/RWT
RT: xxxxxh HGBS:xxx
STAGE:xx CP:x HUCP:x