Step 21 — Install Unit Accessories — For appli- cations requiring accessories, the following packages are available:
All units:
•barometric relief
•space temperature sensor
•CO2 sensor
•space temperature sensor with CO2 sensor
•airflow switch
•filter switch
•smoke detector
All 48P2,P4 (constant volume) units:
•modulating power exhaust
All 48P3,P5 (variable air volume) units:
•modulating power exhaust
Refer to the individual accessory installation instructions in each accessory package for information on installing accessories.
CONTROLS INSTALLATION
Constant Volume (CV) Units — The 48P2,P4 units may be used in applications with additional control features, options, or accessories. Refer to the appropriate accessory installation instructions for more information on installing that accessory. Control options and accessories available for CV units are:
•thermostats
•enthalpy sensor
•enthalpy switch
•relative humidity sensor
•CEM (controls expansion module)
•Navigator™ hand-held display
CONTROL WIRING — The unit can be controlled with a Carrier-approved accessory electro-mechanical or electronic thermostat that has two stages of cooling, two stages of heating control, and an output for fan control. The thermostat may also include time of day scheduling or use scheduling routines built into the ComfortLink™ controls.
Install the thermostat according to the installation instruc- tions shipped with the accessory thermostat. Locate thermostat assembly on a solid interior wall to sense average temperature.
Route thermostat cable or equivalent leads of colored wire from subbase terminals through conduit into the low voltage connections in the main control box. For thermostat TB201 connections, see Fig. 71.
NOTE: For wire runs up to 50 ft, use no. 18 AWG (American Wire Gage) insulated wire (35 C minimum). For over 75 ft, use no. 14 AWG insulated wire (35 C minimum). All wire larger than no. 18 AWG cannot be directly connected at the thermostat and will require a junction box and splice at the thermostat.
Variable Air Volume (VAV) Units — The 48P3,P5 units may be used in applications with additional control fea- tures, options, or accessories. Refer to the appropriate accesso- ry installation instructions for more information on installing that accessory. Refer to the Controls and Troubleshooting man- ual for more information concerning installation and configura- tion of options and accessories. Control options and accessories available for VAV units are:
•enthalpy sensor
•enthalpy switch
•relative humidity sensor
•CEM (controls expansion module)
•Navigator hand-held display
VAV CONTROL WIRING — The recommended types of control wiring are shown below:
| MANUFACTURER | PART NO. |
| Regular Wiring | Plenum Wiring |
| |
| Alpha | 1895 | — |
| American | A21451 | A48301 |
| Belden | 8205 | 884421 |
| Columbia | D6451 | — |
| Manhattan | M13402 | M64430 |
| Quabik | 6130 | — |
SENSORS — Sensors should be wired using single twisted pairs of 20 AWG (American Wire Gage) conductor cable rated for the application, except for the T-56 accessory sensor which requires 3-conductor cable.
HUMIDITY CONTROL AND HOT WATER AND STEAM VALVES — These devices require 20 AWG twisted pair conductor cables rated for the application for the 4 to 20 mA signal.
SPACE TEMPERATURE SENSOR (T-55) — The space tem- perature sensor (P/N 33ZCT55SPT), if used, is wired to termi- nals in the unit main control box. To connect the space temper- ature sensor, see Fig. 72.
SPACE TEMPERATURE SENSOR (T-56) — The space tem- perature sensor (P/N 33ZCT56SPT), if used, is wired to termi- nals in the unit main control box. To connect the space temper- ature sensor, see Fig. 72.
COMMUNICATING SPACE TEMPERATURE SENSOR (T-58) — The communicating space temperature sensor (P/N 33ZCT58SPT) is wired to the Carrier Comfort Network® (CCN) connections on TB202.
SPACE TEMPERATURE AVERAGING — Applications that require averaging using multiple space temperature sensors can be satisfied using either 4 or 9 sensors as shown in Fig. 73.
NOTE: Only Carrier sensors may be used for standard T-55 space averaging. Sensors must be used in multiples of 1, 4, and 9 only, with total sensors wiring not to exceed 1000 ft.
NOTE: Do not use T-56 sensors for space temperature averag- ing because the 5-degree offset function will not work in a multiple sensor application.
HEAT INTERLOCK RELAY (VAV Units Only — Not Neces- sary for Digital Air Volume Applications) — Variable air vol- ume (VAV) units using morning warm-up and/or occupied heating require that room terminals be controlled to a position that provides the minimum required heating cfm or greater when the unit goes into Heating mode. The HIR (heat interlock relay) function is provided for this control. When the unit goes into Heating mode, the HIR is energized to provide switch clo- sure or opening (depending on how the field-supplied power source is set up) to open the room terminals. The field connec- tions for the HIR are at TB201 terminals 9 and 10. See Fig. 74.
Option and Accessory Control Wiring — The P Series units may be used in applications with additional control features, options, or accessories. Refer to the Controls and Troubleshooting manual for more information concerning installation and configuration of options and accessories. Figures 74-84 contain wiring information on the following features:
•heat interlock relay (Fig. 74)
•outdoor air enthalpy switch (Fig. 75)
•CO2 space sensor (Fig. 76)
•filter status switch (Fig. 77)
•fan status switch (Fig. 78)
•space humidity sensor (Fig. 79)
•return air humidity sensor (Fig. 79)
•return air CO2 sensor (Fig. 80)
•return air smoke detector (Fig. 81)
•smoke control — fire shutdown (Fig. 82)