Carrier 37MUHAQ36AA3 - User Manual

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Specifications subject to change without notice.

TABLE OF CONTENTS

PAGE

A NOTE ABOUT SAFETY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

INDOOR UNIT PARTS AND MAJOR FUNCTIONS . . . . . . . . . . . 7

CONTROLS OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

WIRELESS REMOTE CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . 9

OPERATION INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

CARE AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

ERROR CODES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

NOTE TO EQUIPMENT OWNER:

Please read this Owner’s Information Manual carefully before installing and using this appliance and keep this manual for future

reference.

For your convenience, please record the model and serial numbers of your new equipment in the spaces provided. This information, along

with the installation data and dealer contact information, will be helpful should your system require maintenance or service.

UNIT INFORMATION

Model # _______________________________

Serial # ________________________________

INSTALLATION INFORMATION

Date Installed ___________________________

DEALERSHIP CONTACT INFORMATION

Company Name: ______________________

Address:_____________________________

Phone Number:________________________

Technician Name:______________________

Owner’s Manual

45MUAAQ

Crossover Air Handler

Sizes 18K - 60K

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Do you have a question about the Carrier 37MUHAQ36AA3 and is the answer not in the manual?

The 45MUAAQ Crossover Air Handler is an indoor unit designed to provide quiet, maximum comfort in residential settings. It is compatible with outdoor condensing units (37MUHAQ and 37MURAQ models) and offers cooling, heating, filtering, and dehumidification functionalities. This air handler is available in various sizes, ranging from 18K to 60K, with nominal air volumes from 400 CFM (680 m³/h) to 795 CFM (1350 m³/h). It utilizes R-454B, a mildly flammable refrigerant (Safety Group A2L), and requires careful handling and installation in compliance with national regulations.

Function Description:

The 45MUAAQ Crossover Air Handler operates in five modes:

FAN Only: Circulates and filters room air without changing its temperature.
AUTO: Automatically selects COOL or HEAT mode based on the user-selected set point. Heating is prioritized, and simultaneous heating and cooling are not allowed.
HEATING: Heats and filters room air (available for heat pump systems only).
COOLING: Cools, dries, and filters room air.
DEHUMIDIFICATION (DRY): Dries, filters, and slightly cools room air, prioritizing dehumidification. This mode does not replace a dedicated dehumidifier.

Important Technical Specifications:

Refrigerant: R-454B (mildly flammable, Safety Group A2L).
Sizes: 18K, 24K, 30K, 36K, 48K, 60K.
Nominal Air Volume:
- 18K/24K: 400 CFM (680 m³/h)
- 30K: 447 CFM (760 m³/h)
- 36K: 541 CFM (920 m³/h)
- 48K: 706 CFM (1200 m³/h)
- 60K: 795 CFM (1350 m³/h)
Operating Temperature Range:
- COOL Mode (Room): 60°F - 90°F (16°C - 32°C)
- HEAT Mode (Room): 32°F - 86°F (0°C - 30°C)
- Dry Mode (Room): 50°F - 90°F (10°C - 32°C)
- Outdoor Temperature (Hyper Heat Series):
  - Cooling: -22°F - 122°F (-30°C - 50°C)
  - Heating: -22°F - 75°F (-30°C - 24°C)
- Outdoor Temperature (Regular Heat Series):
  - Cooling: -13°F - 122°F (-25°C - 50°C)
  - Heating: -13°F - 75°F (-25°C - 24°C)
Room Relative Humidity: Less than 80% for optimal operation to prevent condensation.
Refrigerant Leak Detection System: Equipped with a sensor that detects refrigerant leakage, triggers an error code (EHC1, EHC2, EHC3, ECC1, ELOC), emits a buzzing sound, stops the outdoor compressor, and starts the indoor fan. The sensor has a service life of 15 years and can only be replaced by the manufacturer.
Power Failure Auto-Restart: Stores operating conditions and restarts automatically with the same settings when power is restored.
Three-Minute Protection Feature: Prevents immediate restart after operation stops, protecting the compressor.
Heat Exchanger Dust Removal Function: When turned off, the outdoor fan runs in reverse for 70 seconds to clear dust and debris from the heat exchanger.

Usage Features:

The unit can be controlled via:

Wireless Remote Control (Included): A handheld remote (RG10F8(2)/BGEFU1) provides full control over operating modes, temperature settings (60-86°F / 16-30°C), fan speed (AU, 20%, 40%, 60%, 80%, 100%), and timer functions (TIMER ON/OFF). It also features a TURBO mode for rapid cooling/heating, a SLEEP mode for energy conservation, and an LED button to control the indoor unit's display light. The remote can display temperature in °F or °C.
Wired Controller (Optional): KSACN1401AAA, a non-polarity controller, operates all functions and can be used in conjunction with the wireless controller.
Third-Party Heat Pump Thermostat (Not Included): Allows control via a built-in 24V interface. Note: The wired controller and wireless remote cannot be used when a third-party thermostat is connected.

Operating Modes and Settings:

Temperature Setting: Adjustable in 1°F (0.5°C) increments.
Fan Speed: Selectable in FAN mode. In AUTO or DRY mode, fan speed is automatically set.
Timer Function: TIMER ON and TIMER OFF can be set independently or together to program unit start and stop times, increasing in 30-minute increments up to 10 hours, then 60-minute increments up to 24 hours.
SLEEP Mode: Conserves energy by adjusting the set point (raises by 2°F/1°C after 1 hour, then another 2°F/1°C after another hour in COOL mode; lowers by 2°F/1°C in HEAT mode) and running the fan at low speed. It terminates after 5 hours or if MODE, TEMP, FAN, TIMER, or ON/OFF buttons are pressed.
TURBO Mode: Rapidly cools or heats the room at super high fan speed for 20 minutes. Can be terminated early.
CLEAN Mode: Activates a 30-minute self-cleaning and drying cycle for the evaporator in COOL or DRY mode.
LED Light: Toggles the display light on/off.

Maintenance Features:

Air Filter Cleaning/Replacement: Inspect and clean or replace the air filter monthly or as required. The user needs to purchase a standard filter meeting UL900 requirements. Filters can be vacuumed or washed with warm water and mild detergent.
Long Periods of Non-Use: Before extended non-use, clean all filters, run the FAN function to dry the unit, turn off the unit, disconnect power, and remove remote control batteries.
Pre-Season Inspection: Before frequent use, check for damaged wires, clean filters, check for leaks, ensure air inlets/outlets are clear, and replace remote control batteries.
Troubleshooting: The manual provides a table of common issues and possible causes/solutions. Error codes (e.g., EC07, EH00, EHC1) are displayed on the indoor unit for diagnostic purposes. If problems persist, contact an authorized service center.

Safety Information:

The manual emphasizes safety precautions for installation, operation, and maintenance, especially concerning the flammable R-454B refrigerant. It warns against improper installation, unauthorized repairs, and using non-approved parts. Specific instructions are provided for handling refrigerants, leak detection, ventilation, and electrical safety. The unit and packaging include symbols indicating the presence of flammable refrigerant, the need to read the manual, and requirements for qualified service personnel.