54
PremierLink™ Control
For details on operating units equipped with the factory-installed
PremierLink  controller  option, refer to  the  PremierLink  Retrofit
Rooftop Controller Version 3.x Installation, Start-Up, and Config-
uration Instructions manual.
RTU Open Control System
For details on operating units equipped with the factory-installed
RTU Open controller, refer to the “Factory-Installed RTU Open
Multi-Protocol Controller Control, Start-Up, Operation and Trou-
bleshooting” manual.
SMOKE DETECTORS
Smoke  detectors  are  available  as  factory-installed  options  on
48TC models. Smoke detectors may be specified for supply air
only, for return air without or with economizer, or in combination
of supply air and return air. All components necessary for opera-
tion are factory-provided and mounted. The unit is factory-config-
ured for immediate smoke detector shutdown operation; addition-
al wiring or modifications to unit terminal board may be necessary
to  complete  the  unit  and  smoke  detector  configuration  to  meet
project requirements.
Units  equipped  with  factory-optional return-air  smoke  detectors
require a relocation of the sensor module at unit installation. See
Fig. 78 for the as-shipped location.
COMPLETING  INSTALLATION  OF  RETURN-AIR
SMOKE SENSOR
1. Unscrew  the  two  screws  holding  the  return-air  smoke
detector assembly. See Fig. 79, Step 1.
2. Save the screws.
3. Turn the assembly 90 degrees and then rotate end to end.
Make  sure  that  the  elbow  fitting  is  pointing  down.  See
Fig. 79, Step 2.
4. Screw the sensor and detector plate into its operating posi-
tion using screws from Step 1. See Fig. 79, Step 3.
5. Connect the flexible tube on the sampling inlet to the sam-
pling tube on the basepan.
ADDITIONAL APPLICATION DATA
Refer to the application data sheet titled “Factory-Installed Smoke
Detector, for Small and Medium Rooftop Units 2 to 25 Tons” for
discussions on additional control features of these smoke detectors
including multiple unit coordination.
Fig. 78 — Return Air Smoke Detector; Shipping 
Position
Fig. 79 — Completing Installation of Return Air Smoke Sensor
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Be sure to allow enough time for compressor start-up and shut-
down between checkout tests so that you do not short-cycle the
compressors.
RETURN AIR 
SMOKE DETECTOR
(AS SHIPPED)