Carrier 25HBA3 Series, Product Data

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5
ACCESSORY USAGE GUIDELINE
ACCESSORY
REQUIRED FOR LOW---AMBIENT
COOLING APPLICATIONS
(Below 55
°
F/12.8
°
C)
REQUIRED FOR
LONG LINE
APPLICATIONS*
(Over 80 Ft.)
REQUIRED FOR
SEA COAST
APPLICATIONS
(Within 2 miles)
Accumulator Standard Standard Standard
Ball Bearing Fan Motor Yes
{
No No
Compressor Start Assist Capacitor and Relay Yes
{
Yes No
Crankcase Heater
Yes
{
Yes No
Evaporator Freeze Thermostat Yes
{
No No
Isolation Relay Yes
{
No No
Liquid Line Solenoid Valve
or Hard Shut---Off TXV
Yes
{
See Long---Line
Application Guideline
Yes
Motor Master
®
Control or
Low---ambient Pressure Switch
Yes
{
No No
Support Feet Recommended No Recommended
* For tubing line sets between 80 and 200 ft. and/or 20 ft. vertical differential, refer to Residential Split---System Longline Application Guideline.
{
Required for Low---Ambient Controller MotorMaster
r
Control only. Hard Shut---Off TXV is standard on new Carrier evaporator coils and fan coils.
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 using MotorMaster
r
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. 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.
6. 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.
7. Liquid--Line Solenoid Valve (LLS)
An electrically operated shutoff valve which stops and starts
refrigerant liquid flow in response to compressor operation. It is
to be installed at the outdoor unit to control refrigerant off cycle
migration in the heating mode.
Usage Guideline:
An LLS is required in all long line heat pump
applications to control refrigerant off cycle migration in
the heating mode. See Long Line Guideline.
8. 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.
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 MotorMaster
r
Low--Ambient Controller must be used when cooling operation is
used at outdoor temperatures below 55
_
F (12.8
_
C).
9. MotorMaster
r
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
mode only. For outdoor temperatures down to --20
_
F (--28.9
_
C),
it maintains condensing temperature at 100
_
F
±
10
_
F (37.8
_
C
±
6.5
_
C).
Usage Guideline:
A MotorMaster
r
Low Ambient Controller or
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.
25H
B
A
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