Carrier Base 24ABA3 Product Data page 5

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 MotorMasterr —
2. 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 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.
3. Compressor Start Assist — PTC Type
Solid state electrical device which gives a "soft" boost to the
compressor at each start- -up.
Usage Guideline:
Suggested in installations with marginal power supply.
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 the
chance of liquid slugging.
Usage Guideline:
Required in low ambient cooling applications.
Required in long line applications.
Suggested in all commercial applications.
5. Cycle Protector
The cycle protector is designed to prevent compressor short
cycling. This control provides an approximate 5- -minute delay
after power to the compressor has been interrupted for any
reason, including power outage, protector control trip, thermostat
jiggling, or normal cycling.
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. Low- -Ambient Pressure Switch Kit
A long life pressure switch which is mounted to outdoor unit
service valve. It is designed to cycle the outdoor fan motor in
order to maintain head pressure within normal operating limits
(approximately 100 psig to 225 psig). The control will maintain
working head pressure at low- -ambient temperatures down to 0_F
when properly installed.
Usage Guideline:
A Low- -Ambient Pressure Switch or MotorMasterr
Low- -Ambient Controller must be used when cooling operation is
used at outdoor temperatures below 55_F (12.8_C).
8. MotorMasterr Low- -Ambient Controller
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
Accessory Description and Usage (Listed Alphabetically) (Continued)
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 MotorMasterr
Low- -Ambient Pressure Switch must be used when
cooling operation is used at outdoor temperatures
below 55_F (12.8_C).
Suggested for all commercial applications.
9. Outdoor Air Temperature Sensor
Designed for use with Carrier Thermostats listed in this
publication. This device enables the thermostat to display the
outdoor temperature. This device also
is required to enable special thermostat features such as auxiliary
heat lock out.
Usage Guideline:
Suggested for all Carrier thermostats listed in this
publication.
10. Sound Hood
Wraparound sound reducing cover for the compressor. Reduces
the sound level by about 2 dBA.
Usage Guideline:
Suggested when unit is installed closer than 15 ft to
quiet areas, bedrooms, etc.
Suggested when unit is installed between two houses less
than 10 ft apart.
11. Support Feet
Four stick- -on plastic feet that raise the unit 4 in. above the
mounting pad. This allows sand, dirt, and other debris to be
flushed from the unit base, minimizing corrosion.
Usage Guideline:
Suggested in the following applications:
Coastal installations.
Windy areas or where debris is normally circulating.
Rooftop installations.
For improved sound ratings.
12. 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.
Hard shut off types are available.
NOTE: When using a hard shut off TXV with single phase
reciprocating compressors, a Compressor Start Assist Capacitor
and Relay is required.
Usage Guideline:
Required to achieve ARI ratings in certain equipment
combinations. Refer to combination ratings.
Hard shut off TXV or LLS required in air conditioner
long line applications.
Required for use on all zoning systems.
12. 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:
For improved efficiency ratings for certain
combinations of indoor and outdoor units. Refer to
ARI Unitary Directory.
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Low Ambient Controller or