18 OMM 1008-1
Unit Controller
Table 2, Unit Controller, Analog Inputs
# Description Signal Source Range
1 Reset of Leaving Water Temperature 4-20 mA Current 0-(10 to 80°F)
2
Entering Evaporator Water
Temperature
NTC Thermistor (10k@25°C) -58 to 212°F
3
Entering Condenser Water
Temperature
NTC Thermistor (10k@25°C) -58 to 212°F
4 Leaving Condenser Water Temperature NTC Thermistor (10k@25°C) -58 to 212°F
5 Liquid Line Refrigerant Temperature NTC Thermistor (10k@25°C) -58 to 212°F
6 Demand Limit 4-20 mA Current 0-100 %RLA
7 Evaporator Water Flow 4 to 20 mA Current 0 to 10,000 gpm
8 Condenser Water Flow 4 to 20 mA Current 0 to 10,000 gpm
9 Refrigerant Leak Sensor 4 to 20 mA Current 0 to 100 ppm
10 Leaving Evaporator Water Temperature NTC Thermistor (10k@25°C) -58 to 212°F
Table 3, Unit Controller, Digital Inputs
# Description Signal Signal
1 Unit OFF Switch 0 VAC (Stop) 24 VAC (Auto)
2 Remote Start/Stop 0 VAC (Stop) 24 VAC (Start)
3 Not Used
4 Evaporator Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow)
5 Condenser Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow)
6 Manual Off 0 VAC (Off) 24 VAC (Auto)
7 Evaporator Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow)
8 Condenser Water Flow Switch 0 VAC (No Flow) 24 VAC (Flow)
Table 4, Unit Controller, Digital Outputs
# Description Load Output OFF Output ON
1 Evaporator Water Pump #1 Pump Contactor Pump OFF Pump ON
2 Evaporator Water Pump #2 Pump Contactor Pump OFF Pump ON
3 Condenser Water Pump #1 Pump Contactor Pump OFF Pump ON
4 Condenser Water Pump #2 Pump Contactor Pump OFF Pump ON
5 Tower Fan #1 Fan Contactor Fan OFF Fan ON
6 Tower Fan #2 Fan Contactor Fan OFF Fan ON
7 Spare
8 Alarm Alarm Indicator Alarm OFF Alarm ON
9 Tower Fan #3 Fan Contactor Fan OFF Fan ON
10 Tower Fan #4 Fan Contactor Fan OFF Fan ON
11 Compressor Off Emer. Solenoid
Circuit Breaker
ON
Circuit Breaker
OFF
Table 5, Unit Controller, Analog Outputs
# Description Output Signal Range
1 Cooling Tower Bypass Valve Position 0 to 10 VDC 0 to 100% Open
2 Cooling Tower VFD Speed 0 to 10 VDC 0 to 100%
3 EXV signal to IB Valve Control Bd. 0 to 10 VDC 0 to 100%
4 Y3 Electronic Expansion Valve 0 to 10 VDC 0 to 100% Open
Unit Controller Setpoints
The following parameters are remembered during power off, are factory set to the Default value, and can be
adjusted to any value in the Range column.
The “Type” column defines whether the setpoint is part of a coordinated set of duplicate setpoints in different
controllers. There are three possibilities as given below:
N = Normal setpoint - Not copied from, or copied to, any other controller.
M = Master setpoint - Setpoint is copied to all controllers in the “Sent To” column.
S = Slave setpoint - Setpoint is a copy of the master setpoint (in the unit controller).
To Next Page
Loading...
