Contents

Owners Information Manual
- A170030
- Fig. 1 Unit 48VT
Safety Considerations
- NOTE: Installer: This manual should be left with the equipment user.
  - 1. Do not turn off the electrical power to unit without first turning off the gas supply.
  - 2. Before attempting to start the gas heating section, familiarize yourself with all the procedures that must be followed.
Unit Introduction
- Starting or Shutting Off Unit
- NOTE: Your combination heating/cooling unit is equipped with an automatic direct spark ignition and power combustion blower.
  - 1. Set the temperature selector on room thermostat to the lowest temperature setting and set system switch to Emergency Heat.
  - 2. Close the external manual gas shutoff valve.
  - 3. Turn off the electrical supply to the unit.
  - 4. Remove the control access panel with a 5/16-in. nut driver. (See Fig. 2.)
  - Fig. 2 Unit Access Panels
    - 5. Move the selector switch on the internal gas valve to the OFF position and wait 5 minutes.
    - 6. Move the selector switch on the internal gas valve to the ON position.
    - 7. Replace the control access panel.
    - 8. Turn on the electrical supply to unit.
    - 9. Open the external manual gas shutoff valve.
    - 10. Set the temperature selector on room thermostat slightly above room temperature to start unit. The induced-draft combustion air fan will start. Main gas valve will open and main burners should ignite within 5 seconds. If the burner does not light...
    - 11. Set the temperature selector on room thermostat to desired setting.
      - 1. If the main burners fail to light, or the blower fails to start, shut down gas heating section and call your dealer for service.
      - 2. Never attempt to manually light the main burners on unit with a match, lighter, or any other flame. If the electric sparking device fails to light the main burners, refer to the following shutdown procedures, then call your dealer as soon as possible
  - Fig. 3 Gas Heating/Electric Cooling Unit with Access Panel Removed
  - To shut off unit gas heat:
- NOTE: If the unit is being shut down because of a malfunction, call your dealer as soon as possible.
  - 1. Set the temperature selector on room thermostat to lowest temperature setting and set system SWITCH to OFF.
  - 2. Close the external manual shutoff valve.
  - 3. Turn off the electrical power supply to the unit.
  - 4. Remove the control access panel. (See Fig. 2.)
  - 5. Move the selector switch on the internal gas valve to the OFF position.
  - 6. Replace the control access panel.
  - A07662
  - Fig. 4 To Start Unit Gas Heat
    - A07663
  - Fig. 5 To Shut Off Unit Gas Heat
    - A09194
  - Fig. 6 To Start Unit Electric Cooling
    - A07797
  - Fig. 7 To Shut Off Unit Electric Cooling
    - To start unit electric cooling:
      - 1. Set the temperature selector on room thermostat to highest temperature setting and set system SWITCH to OFF.
      - 2. Close the external manual shutoff valve, if not already closed.
      - 3. Turn ON the electrical power supply to the unit.
      - 4. Set system switch to COOL.
      - 5. Set the temperature selector on room thermostat slightly below the room temperature to start unit.
    - To shut off unit electric cooling:
      - 1. Set the temperature selector on room thermostat to highest temperature setting and set system SWITCH to OFF.
      - 2. Close the external manual shutoff valve, if not already closed.
      - 3. Turn off the electrical power supply to the unit.
- NOTE: Heat Pump heating mode procedure is similar to electric cooling mode except thermostat mode is HEAT and thermostat must operate on first stage heating above the balance point that has been determined by the Dealer.
Operating Your Unit
- 1. During heat pump heating, increasing the thermostat setting more than 2F (1.1C) may cause the supplemental gas heat to be turned on for a short period of time to satisfy the thermostat. Needless use of the supplementary heat reduces potential ...
- 2. Ice or frost tends to form on the coil during winter heating operation. Your heat pump is designed to automatically melt the ice. When in this defrost cycle, it is normal for steam or fog to rise from the outdoor unit. Do not be alarmed!
- Cooling Mode
- Heat Pump Heating Mode
- Gas Heat Mode
- Defrost Mode
- Emergency Heat Mode
Maintenance and Service
- Routine Maintenance
- Maintenance and Care for the Equipment Owner
  - 1. Turn off gas supply first, then all electrical power to your unit and install lock--out tag before servicing or performing maintenance.
  - 2. When removing access panels or performing maintenance functions inside your unit, be aware of sharp sheet metal parts and screws. Although special care is taken to reduce sharp edges to a minimum, be extremely careful when handling parts or reachi...
  - Air Filters
    - Table 1 Replacement Filter Sizes
      - 1. Remove the filter access panel using a 5/16-in. nut driver.
      - 2. Remove the filter(s) by pulling it out of the unit. If the filter(s) is dirty, clean or replace with a new one.
      - 3. Reinstall filter access panel ensuring opening is air and watertight.
- Replacing or inspecting filters in units with economizers
  - Small Chassis (See Fig. 8)
    - 1. Remove return air duct cover at rear of unit using a 5/16-in. nut driver.
    - 2. Remove the filter(s) by pulling it out and through the unit duct opening. If filter is dirty, replace both filters with new ones.
    - 3. Reinstall duct cover ensuring opening is air and watertight.
  - Large Chassis (See Fig. 9)
    - 1. Remove filter access door using a 5/16-in. nut driver.
    - 2. Remove the filter(s) by pulling it out and through the unit filter access door. If filter is dirty, replace both filters with new ones.
    - 3. Reinstall filter access door ensuring opening is air and watertight.
    - Fig. 8 Small Chassis Filter Access
    - Fig. 9 Large Chassis Filter Access
  - Fans and Fan Motors
  - Indoor and Outdoor Coils
  - Condensate Drain
  - Compressor
  - Condenser (Outdoor) Fan
- Electrical Controls and Wiring
- Refrigerant Circuit
- Unit Panels
- Combustion Area and Vent System
  - Regular Dealer Maintenance (Also refer to (Table 2))
    - 1. Inspection of all flue product passages-including the burners, heat exchanger, and flue collector box, Mare sure the burner flames are blue in color and in proper adjustment. Refer to Fig. 10 for burner flame.
    - 2. Inspection of all combustion-and ventilation-air passages and openings.
    - 3. Close inspection of all gas pipes leading to and inside of your unit.
    - 4. Inspection and, if required, cleaning of the outdoor and indoor coils.
    - 5. Inspection and, if required, cleaning of the indoor coil condensate drain pan.
    - 6. Inspection and cleaning of blower wheel housing and motor.
    - 7. Inspection of all supply-air and return-air ducts for leaks, obstructions, and insulation integrity. Any problems found should be resolved at this time.
    - 8. Inspection of the unit base to ensure that no cracks, gaps, etc., exist which may cause a hazardous condition.
    - 9. Inspection of the unit casing for signs of deterioration.
    - 10. Inspection of all electrical wiring and components to assure proper connection.
    - 11. Inspection for leaks in the refrigerant circuit. Pressure and temperature check to determine appropriate refrigerant charge.
    - 12. Operational check of the unit to determine working conditions. Repair or adjustment should be made at this time.
  - Warranty Certificate
  - Before you call for service...
  - In Case of Trouble
    - Fig. 10 Monoport Burner
    - Table 2 Maintenance Checklist

Carrier 48VT Owner's Manual

Pages 10

Year 2020

Language(s)

of 10

Carrier 48VT Specification

The Carrier 48VT is a versatile rooftop unit designed to deliver efficient heating and cooling solutions for commercial applications. This unit combines advanced technology with robust construction, ensuring reliability and performance in diverse environmental conditions. It utilizes a scroll compressor known for its durability and energy efficiency, reducing operational costs while maintaining optimal climate control. The 48VT is available in various capacities, typically ranging from 3 to 25 tons, catering to different space requirements.

The unit features a high-efficiency gas heat exchanger that enhances heating performance and energy savings. It also incorporates an environmentally friendly Puron refrigerant to minimize environmental impact and comply with modern regulatory standards. The advanced control system allows for precise temperature management, integrating with building management systems to optimize energy usage further.

The 48VT is constructed with a galvanized steel cabinet, providing resistance to corrosion and extending the unit's lifespan. Its design includes easy access panels for streamlined maintenance and servicing, reducing downtime and service costs. Additionally, the unit offers flexible installation options, with multiple airflow configurations to accommodate various building designs and ductwork layouts.

In terms of safety and compliance, the Carrier 48VT meets or exceeds industry standards, ensuring dependable operation and peace of mind for building operators. Its innovative features and robust design make it an ideal choice for commercial establishments seeking a reliable, efficient, and environmentally conscious HVAC solution.

Carrier 48VT F.A.Q.

How do I adjust the thermostat settings on the Carrier 48VT unit?

To adjust the thermostat settings on the Carrier 48VT, locate the thermostat control panel on your wall or within the unit. Use the up and down arrows to set the desired temperature. Ensure the system is set to 'Heat' or 'Cool' depending on your needs.

What are the recommended maintenance routines for the Carrier 48VT?

Recommended maintenance for the Carrier 48VT includes checking and replacing air filters every 1-3 months, inspecting ductwork for leaks annually, and scheduling professional inspections bi-annually to ensure optimal performance.

How can I troubleshoot if the Carrier 48VT is not cooling properly?

If the Carrier 48VT is not cooling properly, check the thermostat settings to ensure it's set to 'Cool'. Verify that the air filters are clean and unobstructed. Inspect the outdoor unit for debris and ensure the condenser coils are clean.

What should I do if the Carrier 48VT unit is making unusual noises?

Unusual noises from the Carrier 48VT may indicate loose parts or debris in the unit. Turn off the system and inspect the fan and motor for obstructions. Tighten any loose screws or panels. If the noise persists, contact a professional technician.

How do I reset the Carrier 48VT unit after a power outage?

To reset the Carrier 48VT after a power outage, turn off the thermostat and the main power switch to the unit. Wait for about 5 minutes before turning the power back on and resetting the thermostat to the desired settings.

What should I check if the Carrier 48VT is not turning on?

If the Carrier 48VT is not turning on, ensure the thermostat is set correctly and the circuit breaker has not tripped. Check the power supply to the unit and ensure all connections are secure.

How often should the air filters be replaced in the Carrier 48VT?

Air filters in the Carrier 48VT should be checked monthly and replaced every 1-3 months, depending on usage and environmental factors, to ensure efficient airflow and system performance.

Can I install the Carrier 48VT unit myself, or do I need a professional?

While basic maintenance can be performed by the user, installation and major repairs of the Carrier 48VT should be conducted by a certified HVAC professional to ensure safety and compliance with local regulations.

What is the best way to clean the condenser coils on the Carrier 48VT?

To clean the condenser coils on the Carrier 48VT, turn off the unit and remove any debris around the condenser. Use a soft brush or coil cleaner to gently clean the coils, and rinse with water if necessary. Ensure the unit is dry before turning it back on.

How can I improve the energy efficiency of my Carrier 48VT unit?

To improve energy efficiency, regularly clean and replace air filters, seal duct leaks, maintain proper refrigerant levels, and schedule annual maintenance checks to ensure all components are functioning efficiently.