SECTION 5

TROUBLESHOOTING

 

 

REMEDY/

CONDITION

POSSIBLE CAUSE

REFERENCE

 

 

SECTION

5.1 UNIT WILL NOT START OR STARTS THEN STOPS

 

 

 

 

 

External power source OFF

Turn on

 

 

 

No power to unit

Start-Stop switch OFF or defective

Check

 

Circuit breaker tripped or OFF

Check

 

 

 

 

Circuit breaker OFF or defective

Check

Loss of control power

Control transformer defective

Replace

 

 

Fuse (F3) blown

Check

 

 

 

 

 

Start-Stop switch OFF or defective

Check

 

 

 

 

Evaporator fan motor internal protector open

6.17

 

 

 

 

Condenser fan motor internal protector open

6.12

 

 

 

 

Compressor internal protector open

6.8

 

 

 

Component(s) Not Operating

High pressure switch open

5.7

 

Heat termination thermostat open

Replace

 

 

 

 

Loss of communication with expansion module

Check Wiring

 

 

 

 

Malfunction of current sensor

Replace

 

 

 

 

Low line voltage

Check

 

 

 

Compressor hums, but does not

Single phasing

Check

start

Shorted or grounded motor windings

6.8

 

 

 

 

Compressor seized

6.8

 

 

 

5.2 UNIT OPERATES LONG OR CONTINUOUSLY IN COOLING

 

 

 

 

Container

Hot load

Normal

 

 

Defective box insulation or air leak

Repair

 

 

 

 

 

Shortage of refrigerant

6.7.1

 

 

 

 

Evaporator coil covered with ice

5.6

 

 

 

 

Evaporator coil plugged with debris

6.15

 

 

 

 

Evaporator fan(s) rotating backwards

6.15/6.17

 

 

 

 

Defective evaporator fan motor/capacitor

6.18

 

 

 

 

Air bypass around evaporator coil

Check

 

 

 

 

Controller set too low

Reset

 

 

 

Refrigeration System

Compressor service valves or liquid line shutoff valve par-

Open valves

tially closed

completely

 

 

Dirty condenser

6.11

 

 

 

 

Compressor worn

6.8

 

 

 

 

Current limit (function code Cd32) set to wrong value

3.5.5

 

 

 

 

Suction modulation valve lost track of step count

Power cycle

 

 

 

 

Suction modulation valve malfunction

6.20

 

 

 

 

Economizer solenoid valve or TXV malfunction

6.14, 6.19

 

 

 

 

Unloader valve stuck open

6.19

5-1

T-309

Page 60
Image 60
Carrier 69NT20-531-300 manual Section Troubleshooting

69NT20-531-300 specifications

The Carrier 69NT20-531-300 is a cutting-edge rooftop unit designed to meet the demanding requirements of commercial heating and cooling applications. This model embodies Carrier’s commitment to energy efficiency, reliability, and advanced technological features that enhance indoor comfort while minimizing operational costs.

One of the standout features of the Carrier 69NT20-531-300 is its high energy efficiency. It is equipped with advanced compressor technology that optimizes performance while reducing energy consumption. This ensures that businesses can maintain a comfortable indoor climate without incurring exorbitant utility bills. With a high Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ratio (EER), users can expect not only enhanced comfort but also significant cost savings over time.

The cooling capabilities of the 69NT20-531-300 are complemented by its robust heating options. This unit utilizes a gas heat exchanger, ensuring quick and even heating throughout the space. The combination of cooling and heating capabilities in one compact unit makes it a versatile choice for various applications, including retail spaces, offices, and warehouses.

In addition to its impressive performance specifications, the Carrier 69NT20-531-300 incorporates innovative technologies that further enhance its functionality. The unit comes with advanced controls, allowing for precise temperature regulation and zoning capabilities. This ensures that different areas of a building can maintain their desired temperatures based on usage, improving overall energy efficiency.

Durability is another hallmark of the Carrier 69NT20-531-300. The unit is constructed with high-quality materials and features a weather-proof cabinet that protects it from the elements, ensuring long-term reliability even in harsh conditions. Furthermore, its modular design simplifies maintenance, making it easy for technicians to access critical components.

The 69NT20-531-300 is also designed with low noise operation in mind. It employs sound-dampening technology to ensure that operations are quiet, making it an ideal choice for locations where noise reduction is a priority, such as schools or healthcare facilities.

Overall, the Carrier 69NT20-531-300 stands out as a premier choice for businesses looking for an efficient, reliable, and feature-rich rooftop HVAC unit. Its blend of energy efficiency, advanced technology, and durability positions it as a leader in commercial heating and cooling solutions, making it a valuable investment for any commercial property.