Bryant 127A - Manual (Page 4)

4
Table 2 – Accessory Usage
ACCESSORY
REQUIRED FOR LONG LINE
APPLICATIONS*
REQUIRED FOR
SEA COAST
APPLICATIONS
(Within 2 miles/3.22 km)
Ball Bearing Fan Motor No No
Compressor Start Assist Capacitor and Relay Yes No
Crankcase Heater Yes No
Evaporator Freeze Thermostat No No
Hard Shut---Off TXV Yes Yes
Liquid Line Solenoid Valve No No
Motor Master ® or Low---ambient Pressure Switch No No
Support Feet No Recommended
Winter Start Control No No
* For tubing line sets between 80 and 200 ft. (24.38 and 60.96 m) and/or 35 ft. (10.7 m) vertical differential, refer to Residential Split---System Longline
Application Guideline.
{ Additional requirement for Low---Ambient Controller (full modulation feature) MotorMasterr Control.
Make Electrical Connections
Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within limits shown
on unit rating plate. Contact local power company for correction of
improper voltage. See unit rating plate for recommended circuit
protection device.
NOTE: Operation of unit on improper line voltage constitutes
abuse and could affect unit reliability. See unit rating plate. Do not
install unit in system where voltage may fluctuate above or below
permissible limits.
NOTE: Use copper wire only between disconnect switch and unit.
NOTE: Install branch circuit disconnect of adequate size per NEC
to handle unit starting current. Locate disconnect within sight from
and readily accessible from unit, per Section 440--14 of NEC.
Route Ground and Power Wires
Remove access panel to gain access to unit wiring. Extend wires
from disconnect through power wiring hole provided and into unit
control box.
!
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or
death.
The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault should
occur. The ground may consist of electrical wire or metal
conduit when installed in accordance with existing electrical
codes.
Connect Ground and Power Wires
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor as shown in Fig. 5.
DISCONNECT
PER N.E.C. AND/OR
LOCAL CODES
CONTACTOR
GROUND
LUG
FIELD GROUND
WIRING
FIELD POWER
WIRING
BLUE 3 PHASE ONLY
A94025
Fig. 5 -- Line Connections
Connect Control Wiring
Route 24--v control wires through control wiring grommet and
connect leads to control wiring (See Fig. 7). Refer to Installation
Instructions packaged with thermostat.
Use No. 18 AWG color--coded, insulated (35_C minimum) wire. If
thermostat is located more than 100 ft. (30.48 m) from unit, as
measured along the control voltage wires, use No. 16 AWG
color--coded wire to avoid excessive voltage drop.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.
Use furnace transformer, fan coil transformer, or accessory
transformer for control power, 24v/40va minimum.
NOTE:
Use of available 24v accessories may exceed the
minimum 40va power requirement. Determine total transformer
loading and increase the transformer capacity or split the load with
an accessory transformer as required.
Final Wiring Check
IMPORTANT: Check factory wiring and field wire connections
to ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
Compressor Crankcase Heater
When equipped with a crankcase heater, furnish power to heater a
minimum of 24 hr before starting unit. To furnish power to heater
only, set thermostat to OFF and close electrical disconnect to
outdoor unit.
A crankcase heater is required if refrigerant tubing is longer than
80 ft. (24.38 m). Refer to the Application Guideline and Service
Manual Longline Section--Residential Split--System Air
Conditioners and Heat Pumps.
Airflow Selections (ECM Furnaces)
The ECM Furnaces provide blower operation to match the
capacities of the compressor during high and low stage cooling
operation. Tap selections on the furnace control board enable the
installing technician to select the proper airflows for each stage of
cooling. Below is a brief summary of the furnace airflow
configurations
1. The Y2 call for high stage cooling energizes the “Cool” tap
on the control board. The grey wire from cool tap is connec-
ted to tap 5 on the motor. Refer to the furnace Product Data
to find the corresponding airflow. If the airflow setting for
high cooling needs to be switched from tap 5 to a different
tap, jumper a connection from the cool tap to the desired tap
so that the Y2 signal is communicated via the cool tap to the
desired speed tap.
2. The Y1 call for low stage cooling energizes the “Fan” tap
on the control board. The red wire from the fan tap is con-
nected to tap 1 on the motor. Refer to the furnace Product
Data to find the corresponding airflow. If the airflow setting
for low cooling needs to be switched from tap 1 to a differ-
ent tap, jumper a connection from the Fan tap to the desired
tap so that the Y1 signal is communicated via the Fan tap to
the desired speed tap. The Y1 setting will also govern the
continuous fan airflow for the furnace.
Refer to the literature for the furnace for further details.
127A