Reznor RCB User Manual

Form CP-MAPSIII-D21, Doc No 303070, Page 13
SpcClgOffDiff: Space Cooling on Differential 1°F(.4°C) = 77°F(25°C)
Space Temp less than or equal to 77°F(25°C) = Unit OFF.
Intermittent Unoccupied Cooling operation will only be permitted in the unit cool state.
3.7.3 Space Dehumidication Control
SpcHumSP: Space Humidity Setpoint 55%
SpcHumSP: Space Humidity Setpoint 55% plus the SpcDhOnDiff: Space Dehum ON
Differential 10% = 65%
Space Humidity greater than or equal to 65% = Space Dehumidication Mode
ON.
SpcHumSP: Space Humidity Setpoint 55%
SpcHumSP: Space Humidity Setpoint 55% minus the SpcDhOffDiff: Space Dehum
OFF Differential 5% = 50%
Space Humidity less than or equal to 50% = Space Dehumidication Mode OFF.
If the space temperature sensor (Option CL78 th-tune device) is not enabled or has
failed, the logic will ignore the space requirements and operate to maintain neutral air
temperature in the occupied mode.
If the space temperature sensor (Option CL78 th-tune device) is not enabled or has
failed, the unit will remain OFF in the unoccupied mode.
If the th-tune is enabled and fails, an alarm condition is created.
Selected safeties have an adjustable delay to prevent nuisance alarms. All alarms are
time stamp logged. If a critical shutdown alarm occurs, the unit will not restart until the
alarm is cleared via the display or power cycled.
Alarm ID: 1 Unit Safety Alarm (Critical Shutdown Alarm)
The unit is equipped with a safety status relay which is energized in the normal
state.Thecoilofthesafetyrelayispilotedbyanoptionalrestatand/oraduct
smoke detector. If at any time the status of the safety relay (ID3 = Alarm contact
closure opens), the unit will immediately shut down. All mechanical equipment
will be turned OFF. The unit alarm display shall show “Unit Safety Alarm Unit
OFF”. The unit will not restart until the condition has cleared and the alarm is
acknowledged via the unit controller or remote display.
Alarm ID: 2 Supply Fan Failure (Critical Shutdown Alarm)
If, at any time after an adjustable 120-second time delay from a supply fan start
command,(NO1=”ON”)fanoperationdoesnotproveviaairowswitch(ID1=OFF),
the controller shuts down the system. The unit alarm display shall show “Supply
Fan Failure Unit OFF”. The unit will not restart until the alarm is acknowledged
via the unit controller or remote display.
Alarm ID: 4 Low Discharge Temperature Alarm (Critical Shutdown Alarm)
When the heat is called to be ON and the 1st stage is enabled, the low discharge
temperature limit alarm will be allowed. If the Discharge air temperature (U4)
falls below 33°F/1°C (Low Limit Alarm Setpoint) for more than 10 minutes,
the controller shuts down the system. The unit alarm display shall show “Low
Discharge Air Temperature Alarm Unit OFF”. The unit will not restart until the
alarm is acknowledged via the unit controller or remote display.
Alarm ID: 6 Filter Status
 WhenthemainunitlterpressureswitchactivatesID2=ON,theunitalarm
display shall show “Dirty Filter Status Check Filters”. No other action will be
taken by the control system
Alarm ID: 9 Phase Loss (Critical Shutdown Alarm)
If, at any time the phase loss input ID14 shows ON, the unit shuts down. All
equipment will be turned OFF. The unit alarm display shall show “Phase Loss
Unit OFF”. The unit will not restart until the condition has cleared and the alarm is
acknowledged via the unit controller or remote display.
Alarm ID: 10 Outside Air Humidity Sensor Failure
4.0 Safeties and
Alarms
4.1 Alarms

Reznor RCB Specifications

General

Brand	Reznor
Model	RCB
Category	Air Handlers
Language	English