Carrier 25HCR3C warranty MotorMasterr Low-Ambient Controller

Accessory Description and Usage (Listed Alphabetically) - CONTINUED

25HCR3C

11. MotorMasterr Low-Ambient Controller

Afan-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 MotorMasterr 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

Amodulating 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.

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