Carrier 25HCS3C, Product Data

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Accessory Description and Usage (Listed Alphabetically) -- CONTINUED
11. 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
±
5.5
_
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.
12. 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.
13. Outdoor Thermostat
An SPDT temperature--actuated switch which turns on
supplemental electric heaters when outdoor air temperature drops
below a user--selected set point.
Usage Guideline:
Electric supplemental heat applications in non--variable
speed indoor units when electric heat staging is desired.
Usage Guideline:
Some local codes may require limiting the heating head
pressure in the vapor line in some applications.
14. Secondary Outdoor Thermostat
An SPDT temperature--actuated switch which turns on third--stage
of supplemental electric heaters when outdoor air temperature
drops below the second--stage set point.
Usage Guideline:
Outdoor thermostat applications where electric heater is
capable of 3--stage operation.
15. Snow Stand
Coated wire rack which supports unit 18 in. (457.2 mm) above
mounting pad to allow for drainage from unit base.
Usage Guideline:
Suggested in the following applications:
Heat pump installations in heavy snowfall areas.
Heat pump installations in snow drift locations.
Heat pump installations in areas of prolonged
subfreezing temperatures.
All commercial installations.
16. Sound Hood
Wraparound sound reducing cover for the compressor. Reduces the
sound level up to 2 dBA.
Usage Guideline:
Suggested when unit is installed closer than 15 ft
(4.57 m) to quiet areas, bedrooms, etc.
Suggested when unit is installed between two houses less
than 10 ft (3.05 m) apart.
Usage Guideline:
Suggested in the following applications:
Heat pump installations in heavy snowfall areas.
Heat pump installations in snowdrift locations.
Heat pump installations in areas of prolonged
subfreezing temperatures.
All commercial installations.
17. Thermostatic Expansion Valve (TXV) Bi--Flow
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.
Usage Guideline:
Required in all heat pump applications
18. 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:
Accessory required to meet ARI rating, where indoor
not equipped.
25H
C
S
3C