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-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.

13.Your servicing dealer may offer an economical service contract that covers seasonal inspections. Ask for further details.

Complete Service Instructions can be found in the unit Installation, Start-Up and Service Instructions.

BEFORE YOU CALL FOR SERVICE,

CHECK FOR SEVERAL EASILY SOLVED

PROBLEMS

If insufficient heating or cooling is suspected:

( )Check for sufficient airflow. Check the air filter for dirt. Check for blocked return-air or supply-air grilles. Be sure they are open and unobstructed. If these checks do not reveal the cause, call your servicing dealer.

If your unit is not operating at all, check the following list for easy solutions:

( ) If using a thermostat, check to be sure that your thermostat temperature selector is set above the indoor temperature during the heating season, or below the indoor temperature during the cooling season. Be sure the SYSTEM switch in the proper HEAT or COOL position and not in the OFF position.

( ) If ComfortLinkcontrols are used, check Scrolling Marquee to be sure unit is not in SERVICE TEST mode. Check that set points are properly configured. If alarm light is on, check what alarms are active and/or notify the dealer.

(

) Is the electrical supply switch on? Are any fuses blown, or has

the circuit breaker tripped?

(

) During the heating season, check the manual gas shutoff valve.

Is this lever parallel with the pipe, indicating that the valve is open? Or is the lever at the right angle, indicating that the valve is closed? If closed, has the gas been shut off for safety reasons? Otherwise, you may open the valve and follow the start-up procedures listed in this manual.

NOTE: Before proceeding with the next check, turn off the electrical power supply to the unit. Remove the control access door.

( ) During the heating season, check the control dial on the gas valve. Is it in the ON position? If it is not, be sure it has not been turned off for the purpose of safety. If nothing else is incorrect, follow the start-up procedures in this manual.

( ) If your unit still fails to operate, call your servicing dealer for troubleshooting and repairs. Specify the model and serial numbers of your unit. (Record them in this manual in the space provided.) If the dealer knows exactly which unit you have, he may be able to offer suggestions over the phone, or save valuable time through knowledgeable preparation for the service call.

IN CASE OF TROUBLE

If, after performing the above, unit performance is unsatisfactory, shut off the unit and call your dealer.

Dealer’s Name:

Telephone No.: Unit Model:

Unit Serial Number:

TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or classified section of your local telephone directory under the

“Heating Equipment” or “Air Conditioning Contractors & Systems” heading for dealer listing by brand name. Have available the Model No., Series Letter, & Serial No. of your equipment to ensure correct replacement part.

Copyright 2009 Carrier Corp., 7310 W. Morris St. Indianapolis, IN 46231

Printed in the U.S.A.

Edition Date: 11/09

Catalog No: 48H---P---

03SO

 

 

 

Manufacturer reserves the right to change, at any time, specifications and design without notice and without obligation.

Replaces: 48H---

P--- 2SO

11

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Carrier 48HG14---28, 48PM16---28, 48PG20---28, 48HJ20---28 Case of Trouble, If insufficient heating or cooling is suspected

48HG14---28, 48HJ20---28, 48PG20---28, 48PM16---28 specifications

The Carrier 48HG14---28, 48PG20---28, 48HJ20---28, and 48PM16---28 models are part of Carrier's renowned lineup of packaged rooftop units (RTUs), designed for commercial HVAC applications. These units combine advanced technology with efficiency and reliability to deliver comfort in various environments.

One of the key features of these models is their high-efficiency operation. Utilizing environmentally friendly refrigerants, they comply with the latest regulations while offering improved energy performance. The units are designed with an energy-efficient compressor and heat exchange systems, maximizing cooling and heating output while minimizing electricity consumption.

These Carrier models also boast a compact design that facilitates easy installation on rooftops, making them ideal for commercial buildings with limited space. The ergonomic layout includes accessible service points, enabling quick maintenance and reducing downtime. Furthermore, these rooftop units are structurally sturdy, capable of withstanding adverse weather conditions.

Equipped with advanced microprocessor controls, the 48HG14---28, 48PG20---28, 48HJ20---28, and 48PM16---28 models offer precise and customizable temperature control, ensuring a consistent indoor climate. The integrated smart technology allows for easy integration into existing building management systems, providing users with real-time monitoring and diagnostics.

Moreover, the noise reduction features in these units ensure a quieter operation, which is critical for commercial spaces where minimal disruption is desired. To enhance indoor air quality, these models include options for variable speed fans and advanced filtration systems, effectively reducing airborne contaminants and improving overall air comfort.

Another significant characteristic of these Carrier units is their versatility. They can be configured for either cooling-only or heating and cooling applications, making them suitable for various climates and building types. The extended product line offers a range of capacity options, ensuring that users can select the right unit for their specific needs.

In conclusion, the Carrier 48HG14---28, 48PG20---28, 48HJ20---28, and 48PM16---28 models represent a blend of efficiency, durability, and innovative technology. They offer reliable performance, ease of maintenance, and exceptional comfort for commercial buildings, solidifying Carrier's position as a leader in the HVAC industry.