5
Accessory usage guideline
* For tubing line sets between 50 and 175 ft, refer to the Residential Split-System Long-Line Application Guideline.
‡ Required for Low-Ambient Controller (full modulation feature) and MotorMaster Control only.
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 and Relay
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).
Installations with hard shutoff expansion valve on indoor coil.
Units installed with Low-Ambient Controller.
Units installed with Liquid-Line Solenoid Valve.
3. Compressor Start Assist — PTC
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. Cycle Protector
Solid-state timing device which prevents compressor rapid recycling. Control provides an approximate 5-minute delay after power to the compressor has been interrupted
for any reason, including normal room thermostat cycling.
SUGGESTED USE: Installations in areas where power interruptions are frequent.
Where user is likely to play” with the room thermostat.
All commercial installations.
Installations where interconnecting tube length exceeds 50 ft.
High-rise applications.
6. Evaporator Freeze Thermostat
An SPST temperature actuated switch which stops unit operation when evaporator reaches freeze-up conditions.
SUGGESTED USE: All units where Low-Ambient Controller has been added.
7. Filter Drier—Bi-Flow
A device for removing contaminants from refrigerant circulating in a heat pump system: 2-direction flow.
SUGGESTED USE: All field-connected split-system heat pumps.
8. 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 426 ± 10 psig
and resets at 320 ± 20 psig. Provides protection against compressor damage due to loss of outdoor airflow.
SUGGESTED USE: Installations exposed to very dirty” outdoor air.
Installations where condenser inlet air temperature exceeds 125°F.
9. 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.
ACCESSORY
REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(Below 55°F)
REQUIRED FOR
LONG-LINE
APPLICATIONS*
(Over 50 Ft)
Crankcase Heater
Yes
Yes
Evaporator Freeze Thermostat
Yes
No
Accumulator
No
No
Compressor Start Assist
Capacitor and Relay
Yes
Yes
Low Ambient Controller,
MotorMaster® Control,
or
Low-Ambient Pressure Switch
Yes
No
Wind Baffle
See Low-Ambient Instructions
No
Coastal Filter
No
No
Unit Risers
Recommended
No
Liquid-Line Solenoid Valve
or
Hard Shutoff TXV
No
See Long-Line
Application
Guideline
Ball Bearing Fan Motor
Yes‡
No
