Bryant R-22 Accessory Descriptions, Crankcase Heater, Evaporator Freeze Thermostat, Wind Baffle

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

Afan-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 all Bryant thermostats listed in this publication.

6. Thermostatic Expansion Valve (TXV)

Amodulating 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 ARI rating and system reliability, where indoor not equipped.

Hard shut off TXV or LLS required in heat pump long line applications.

Required for use on all zoning systems.

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 ARI 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 and Fig. 2.

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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