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ACCESSORY DESCRIPTION AND USAGE (Listed Alphabetically) Continued
9. High-Pressure Switch
Auto reset SPST switch activated by refrigerant pressure on high side of refrigerant circuit. Cycles compressor off if refrigerant pressure rises to 400 ± 10
psig and resets at 298 ± 20 psig. Provides protection against compressor damage due to loss of outdoor airflow. To prevent rapid compressor recycling,
Cycle Protector can be used with this switch.
SUGGESTED USE: Installations exposed to very ‘‘dirty’’ outdoor air.
Installations where condenser inlet air temperature exceeds 125°F (51.7°C).
10. Inlet Grille Kit
A field-installed enhanced inlet grille to replace the standard inlet grille on residential air conditioners and heat pumps.
SUGGESTED USE: For greater protection against inclement weather, incidental damage, and vandalism.
11. Liquid-Line Solenoid Valve (LSV)
An electrically operated shutoff valve to be installed at the outdoor or indoor unit (depending on tubing configuration) and which stops and starts
refrigerant liquid flow in response to compressor operation. Maintains a column of refrigerant liquid ready for action at next compressor operation cycle.
Note:
Compressor Start Assist–Capacitor/Relay Type must also be used. Do not use with hard shutoff TXV.
SUGGESTED USE: For improved system performance in air conditioners for certain combinations of indoor and outdoor units. Refer to ARI Unitary Directory.
In certain long-line-applications. Refer to Long-Line Application Guideline.
12. Low-Ambient Controller
Head-pressure controller is a cycle control device activated by a temperature sensor mounted on a header tube of the outdoor coil. It is designed to cycle
the outdoor fan motor in order to maintain condensing temperature within normal operating limits (approximately 100°F high and 60°F low).
The control will maintain working head pressure at low-ambient temperatures down to 0°F when properly installed.
SUGGESTED USE: Cooling operation at outdoor temperatures below 55°F (12.8°C).
13. Low-Pressure Switch
Auto reset SPST switch activated by refrigerant pressure on low side of refrigerant circuit. Cycles compressor off if refrigerant pressure drops to about 27
psig. Prevents indoor coil freeze-up due to loss of indoor airflow. Provides protection against compressor damage due to loss of refrigerant charge. To
prevent rapid compressor recycling, Cycle Protector can be used with this switch.
SUGGESTED USE: Where indoor coil is exposed to ‘‘dirty’’ air.
All commercial installations.
14. MotorMaster® Control
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, it maintains condensing temperature at 100°F ± 10°F.
SUGGESTED USE: Cooling operation at outdoor temperatures below 55°F.
All commercial installations.
15. Outdoor Air Temperature Sensor
A device that allows the temperature at a remote location (outdoors) to be displayed at the thermostat
SUGGESTED USE: All corporate programmable thermostats.
16. Sound Hood
Wraparound sound attenuation cover for the compressor. Reduces unit sound level by about 2 dBA.
SUGGESTED USE: Unit installed closer than 15 ft to quiet areas—bedrooms, etc.
Unit installed between 2 houses less than 10 ft apart.
17. 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. Both hard shutoff and RPB valves are available. Do not use hard shutoff TXV
with Liquid-Line Solenoid Valve.
SUGGESTED USE: For improved system performance in cooling mode for certain combinations of indoor and outdoor units. Refer to ARI Unitary Directory.
Required for use on all zoning systems.
18. Time-Delay Relay
An SPST delay relay which briefly continues operation of the indoor blower motor to provide additional cooling after the compressor cycles off.
SUGGESTED USE: For improved efficiency ratings for certain combinations of indoor and outdoor units. Refer to ARI Unitary Directory.
Required for use on all zoning systems.
19. Winter Start Control
An SPST delay relay which bypasses the low-pressure switch for approximately 3 minutes to permit start-up for cooling operation under low-load
conditions.
SUGGESTED USE: All air conditioners where Low-Ambient Controller has been added.
