48TC

1.Remove manifold pressure tap plug from manifold and connect pressure gauge or manometer. (See Fig. 33.)

2.Turn on electrical supply.

3.Turn on unit main gas valve.

4.Set room thermostat to call for heat. If unit has two- stage gas valve, verify high-stage heat operation be- fore attempting to adjust manifold pressure.

5.When main burners ignite, check all fittings, mani- fold, and orifices for leaks.

6.Adjust high-stage pressure to specified setting by turning the plastic adjustment screw clockwise to in- crease pressure, counter-clockwise to decrease pres- sure.

7.For Two-Stage Gas Valves set room thermostat to call for low-stage heat. Adjust low-stage pressure to specified setting.

8.Replace regulator cover screw(s) when finished.

9.With burner access panel removed, observe unit heat- ing operation in both high stage and low stage opera- tion if so equipped. Observe burner flames to see if they are blue in appearance, and that the flames are approximately the same for each burner.

10.Turn off unit, remove pressure manometer and re- place the 1/8 in. pipe fitting on the gas manifold. (See Fig. 32.)

Limit Switch

Remove blower access panel. Limit switch is located on the fan deck. See Fig. 28.

Burner Ignition

Unit is equipped with a direct spark ignition 100% lockout system. Integrated Gas Unit Controller (IGC) is located in the control box. See Fig. 34. The IGC contains a self-diagnostic LED (light-emitting diode). A single LED (see Fig. 38) on the IGC provides a visual display of operational or sequential problems when the power supply is uninterrupted. When a break in power occurs, the IGC will be reset (resulting in a loss of fault history) and the indoor (evaporator) fan ON/OFF times will be reset. The LED error code can be observed through the viewport. During servicing refer to the label on the control box cover or Table 8 for an explanation of LED error code descriptions.

If lockout occurs, unit may be reset by interrupting power supply to unit for at least 5 seconds.

LOW HEAT

72,000 BTUH INPUT AND 60,000 BTUH INPUT

MEDIUM AND HIGH HEAT

115,000 BTUH INPUT,

150,000 BTUH INPUT, 90,000BTUH INPUT AND 120,000 BTUH INPUT

C06154

Fig. 35 - Spark Adjustment (04-07)

26

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Carrier 48TCA04---A12 appendix Burner Ignition, Limit Switch
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48TCA04---A12 specifications

The Carrier 48TCA04---A12 is a high-efficiency rooftop air conditioning unit designed for commercial and industrial applications. Known for its reliability and performance, this model features advanced technologies that cater to diverse climate control needs.

One of the standout features of the Carrier 48TCA04---A12 is its excellent energy efficiency, which adheres to the stringent standards set by the U.S. Environmental Protection Agency. The unit utilizes a highly efficient scroll compressor combined with state-of-the-art heat exchanger technology, allowing it to operate with minimal energy consumption while providing powerful cooling capabilities.

The unit comes equipped with a robust and durable design, built to withstand various environmental conditions. Its weather-resistant cabinet is constructed from high-quality materials, ensuring long-lasting performance even in harsh climates. Additionally, the unit features a galvanized steel structure with a powder-coated finish, further enhancing its resistance to corrosion and wear.

In terms of technologies, the Carrier 48TCA04---A12 incorporates advanced controls that promote optimal performance. The unit supports Carrier's smart connectivity options, facilitating remote monitoring and adjustments via smart devices. This feature ensures convenient energy management and allows maintenance teams to access performance data, leading to proactive service interventions.

Another important characteristic of this unit is its quiet operation. The design includes sound-reducing insulation and a well-engineered airflow system, minimizing noise levels to create a more comfortable indoor environment. This is particularly important for commercial spaces such as offices and retail environments, where a tranquil atmosphere is critical for customer satisfaction and productivity.

The Carrier 48TCA04---A12 also offers diverse application flexibility, making it suitable for various locations, from small retail stores to large warehouses. With several tonnage options available, users can select a model that perfectly aligns with their specific cooling needs. Additionally, the unit can be easily integrated with existing HVAC systems, providing a seamless solution for upgrading or retrofitting older installations.

To sum up, the Carrier 48TCA04---A12 rooftop air conditioning unit stands out due to its exceptional energy efficiency, durable construction, advanced technology, and quiet operation, making it a reliable choice for commercial and industrial cooling solutions. Its flexibility and smart technology integrations ensure that it meets a wide range of climate control requirements effectively.
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