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ACCESSORY USAGE GUIDELINE
* For tubing line sets between 50 and 175 ft, refer to Residential’s Split System Long-Line Application Guidelines.
† For buried line applications, refer to Residential’s Split Systems Buried Line Application Guidelines.
‡ Only when low-pressure switch is used.
ACCESSORY DESCRIPTION AND USAGE (Listed Alphabetically)
1. Ball Bearing Fan Motor
A fan motor with ball bearings which permits speed reduction while maintaining bearing lubrication.
SUGGESTED USE: Required on all units where low-ambient controller (full modulation feature) or MotorMaster® Control has been added.
2. Compressor Start Assist-Capacitor/Relay Type
Start capacitor and start relay gives “hard” boost to compressor motor at each start-up.
SUGGESTED USE: Installations where interconnecting tube length exceeds 50 ft. Installations where outdoor design temperature exceeds 105
°
F (40.6
°
C).
Replacement installations with hard shutoff expansion valve on indoor coil. Units installed with low-ambient controller. Units installed with liquid
solenoid valve.
3. Compressor Start Assist-PTC Type
Solid-state electrical device which gives a “soft” boost to the compressor at each start-up.
SUGGESTED USE: Installations with marginal power supply.
Replacement installations with rapid pressure balance (RPB) expansion valve on indoor coil.
4. 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 chance of refrigerant slugging. May or may not include a thermostat control.
SUGGESTED USE: When interconnecting tube length exceeds 50 ft.
When unit will be operated below 55
°
F (12.8
°
C) outdoor air temperature. (Use with low-ambient controller.)
5. Evaporator Freeze Thermostat
An SPST temperature actuated switch which stops unit operation when evaporator reaches freeze-up conditions.
SUGGESTED USE: With low-ambient controller.
6. Filter Drier—Bi-flow
A device for removing contaminants from refrigerant circulating in a heat pump system; 2-direction flow for heat pumps.
SUGGESTED USE: Split-system heat pumps.
7. Interface Control
An electric control for controlling a heat pump and gas or oil furnace system for maximum energy savings. It allows heat pump to operate down to a predeter-
mined economic balance point temperature, then switches to allow furnace operation only below that temperature. Requires outdoor thermostat (Item 12) to
be adjusted for economic balance point temperature.
SUGGESTED USE: For heat pump and gas- or oil-fired furnace combination systems.
8. 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.
SUGGESTED USE: All heat pumps where low-ambient controller has been added.
9. Liquid Solenoid Valve (LSV)
An electrically operated shutoff valve to be installed at the outdoor unit 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.
SUGGESTED USE: In certain long-line applications. (Refer to Long-Line Application Guideline.)
10. 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 motors in order to maintain condensing temperature within normal operating limits (approximately 130 to 110
°
F high, 70 to 50
°
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).
11. 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 tem-
perature 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.
12. Outdoor Thermostat
An SPDT temperature actuated switch which turns on supplemental electric heaters when outdoor air temperature drops below set point.
SUGGESTED USE: Heat pump installations with multiple-stage supplemental heaters.
ACCESSORY
REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(Below 55
°
F)
REQUIRED FOR
LONG-LINE
APPLICATIONS*
(Over 50 Ft)
REQUIRED FOR
BURIED LINE
APPLICATIONS†
(Over 3 Ft)
REQUIRED FOR
SEA COAST
APPLICATIONS
(Within 2 Miles)
Crankcase Heater Yes Yes Yes No
Evaporator Freeze Thermostat Yes No No No
Winter Start Control Yes‡ No No No
Accumulator No No Yes No
Compressor Start Assist
Capacitor and Relay Yes Yes Yes No
Low Ambient Controller
or
MotorMaster® Control Yes No No No
Wind Baffle
See Low-Ambient
Instructions
No No No
Coastal Filter No No No Yes
Support Feet Recommended No No Recommended
Liquid-Line Solenoid Valve
or
Hard Shutoff TXV No
See
Long-Line
Application Guideline Yes No
Ball Bearing Fan Motor Yes No No No