Accessory Descriptions - Bryant Base Series Application Manual And Service Manual

Residential Air Conditioners and Heat Pumps Using R-22 and Puron® Refrigerant: Application Guideline and Service Manual

ACCESSORY DESCRIPTIONS

Refer to Table 1 for an Accessory Usage Guide for Air Conditioners and
Table 2 for Heat Pumps. Refer to the appropriate section below for a
description of each accessory and its use.
1. Crankcase Heater
An electric resistance heater which mounts to the base of the compressor
to keep the lubricant warm during off cycles. Improves compressor
lubrication on restart and minimizes the chance of liquid slugging.
Usage Guideline:
Required in low ambient cooling applications.
Required in long line applications.
Suggested in all commercial applications.
2. Evaporator Freeze Thermostat
An SPST temperature-actuated switch that stops unit operation when
evaporator reaches freeze-up conditions.
Usage Guideline:
Required when low ambient kit has been added.
3. Isolation Relay
An SPDT relay which switches the low-ambient controller out of the
outdoor fan motor circuit when the heat pump switches to heating mode.
Usage Guideline:
Required in all heat pumps where low ambient kit has been added
4. Low-Ambient Pressure Switch
A fan-speed control device activated by a temperature sensor, designed
to control condenser fan motor speed in response to the saturated
condensing temperature during operation in cooling mode only. For
outdoor temperatures down to -20°F (-28.9°C), it maintains condensing
temperature at 100°F ± 10°F (37.8°C ± 12°C).
Usage Guideline:
A Low Ambient Controller must be used when cooling operation is
used at outdoor temperatures below 55°F (12.8°C).
Suggested for all commercial applications.
5. Outdoor Air Temperature Sensor
Designed for use with Bryant Thermostats listed in this publication. This
device enables the thermostat to display the outdoor temperature. This
device is required to enable special thermostat features such as auxiliary
heat lock out.
Usage Guideline:
Suggested for approved Bryant thermostats.
6. Thermostatic Expansion Valve (TXV)
A modulating flow-control valve which meters refrigerant liquid flow
rate into the evaporator in response to the superheat of the refrigerant gas
leaving the evaporator.
Kit includes valve, adapter tubes, and external equalizer tube. Hard shut
off types are available.
Usage Guideline:
Accessory required to meet AHRI rating and system reliability, where
indoor not equipped.
Hard shut off TXV or LLS required in heat pump longline
applications.
Required for use on all zoning systems.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7. Time-Delay Relay
An SPST delay relay which briefly continues operation of indoor
blower motor to provide additional cooling after the compressor cycles
off.
NOTE: Most indoor unit controls include this feature. For those that do
not, use the guideline below.
Usage Guideline:
Accessory required to meet AHRI rating, where indoor not equipped.
8. Wind Baffle
Use only in installations where high winds are prevalent to prevent cross
currents from causing abnormal control operation. For construction,
refer to Fig. 1.
NOTE: When wind baffles are used, raising unit off of mounting pad
with 4-in. support feet or unit risers is REQUIRED. This provides better
airflow for moderate and high ambient temperatures.
9. Winter Start Control
This control is designed to alleviate nuisance opening of the
low-pressure switch by bypassing it for the first 3 minutes of operation.
This control is for AC units operating in low ambient cooling but is not
required for Heat Pumps. Heat pumps have a loss of charge switch
rather than a low pressure switch and nuisance trips should not be an
issue.
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