5
Accessory usage guideline
*
For tubing line sets between 50 and 175 ft horizontal or 20 ft vertical differential, refer to Residential Split Systems Long-Line Application Guideline.
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.
Usage Guideline:
Required on all units when MotorMaster®—Low-Ambient Controller is installed.
2.
Coastal Filter
A mesh screen inserted under the top cover and inside the base pan to protect the condenser coil from salt damage without restricting airflow.
3.
Compressor Start Assist – Capacitor and Relay
Start capacitor and relay gives a "hard" boost to compressor motor at each start up.
Usage Guideline:
Required for single-phase reciprocating
compressors in the following applications:
Long line
Low ambient cooling
Hard shut off expansion valve on indoor coil
Liquid line solenoid on indoor coil
Required for single-phase scroll compressors in the following applications:
Long line
Low ambient cooling
Suggested for all compressors in areas with a history of low voltage problems
4.
Compressor Start Assist – PTC Type
Solid-state electrical device which gives a "soft" boost to the compressor motor at each start up.
Usage Guideline:
Suggested when compressor power supply is marginal.
Suggested in reciprocating compressor applications with rapid pressure balance (RPB) expansion valve on indoor coil.
5.
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.
Note:
Some heat pumps are factory supplied with a crankcase heater. See accessory list for units that come standard with a crankcase heater. For units that do
not, use the guideline below.
Usage Guideline:
Required in low ambient cooling applications.
Required in long line applications.
Suggested in all commercial applications.
6.
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.
7.
Filter Drier
A device for removing contaminants from refrigerant circulating in a heat pump system: two-direction flow.
Usage Guideline:
Suggested in 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.
Usage Guideline:
Suggested in installations exposed to "very dirty" outdoor air.
Suggested in installations where condenser inlet air temperature exceeds 125°F (51.7°C).
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.
Usage Guideline:
Required in all heat pumps where low-ambient kit has been added.
ACCESSORY
REQUIRED FOR
LOW-AMBIENT
APPLICATIONS
(Below 55°F)
REQUIRED FOR
LONG-LINE
APPLICATIONS
*
(Over 50 Ft)
REQUIRED FOR
SEA COAST
APPLICATIONS
(Within 2 Miles)
Crankcase Heater
Ye s Yes No
Evaporator Freeze Thermostat
Ye s N o N o
Accumulator
No No No
Compressor Start Assist
Capacitor and Relay
Ye s Yes No
MotorMaster®—Low-Ambient
Controller or Low-Ambient Pressure
Switch
Ye s N o N o
Wind Baffle
See Low-Ambient Instructions No No
Coastal Filter
No No Yes
Support Feet Recommended No Recommended
Liquid-Line Solenoid Valve
or
Hard Shutoff TXV No
See Long-Line
Application
Guideline No
Ball Bearing Fan Motor Ye s N o N o
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