Pre-Start-Up

Unit Preparation Ð Check to see that unit has been installed in accordance with these Installation Instructions and all applicable codes.

Compressor Mounting Ð Loosen compressor hold- down bolts until sidewise movement of the washer under each holddown bolt head can be obtained. Do not loosen completely, as bolts are self-locking and will maintain adjustment.

Evaporator-Fan Shipping Brackets Ð Evapor- ator-fan shipping brackets (4 per unit) must be removed from each corner of the fan sled before starting unit.

UNIT SIZES 034 AND 044

1.To remove brackets, raise fan sled by turning adjusting bolt counterclockwise until spring is compressed slightly.

2.Remove screws holding shipping bracket to unit cross rail.

3.Remove shipping bracket (top of bracket is slotted so that it will slide out).

4.After removing all shipping brackets, level fan sled using the adjusting screws. On all 4 corners, dimension from cross rail to fan sled should be as shown in Fig. 30.

UNIT SIZES 054-074 Ð To remove shipping brackets, re- move the 6 screws holding each bracket to the cross rail. There are 8 brackets per unit. See Fig. 30 or 31.

After removing all shipping brackets, level fan sled using the adjusting screws. On all 4 corners dimension from cross rail to fan sled should be as shown in Fig. 30 or 31.

Internal Wiring Ð Check all electrical connections in the unit control box; tighten as required.

Fig. 30 Ð Shipping Brackets; 034,044 Units and

50 Series Vertical Discharge 054-074 Units

Refrigerant Service Valves Ð All units have a Schrader-type service port on both suction lines. Be sure that caps on the ports are tight. All units have discharge and suc- tion service valves on each compressor and a service valve on each liquid line. Be sure the valves are open before start- ing unit.

Crankcase Heaters Ð The crankcase heaters must be ®rmly locked into the compressors. The crankcase heaters are energized when there is power to the unit. Crankcase heaters must be energized with discharge and suction serv- ice valves open for at least 24 hours prior to unit start-up in order to remove liquid refrigerant from the compressor crank- case and to prevent oil foaming.

Compressor Oil Ð Check that compressor oil is vis- ible in the sight glass of the compressor. All units are factory charged with oil. See Table 8. Observe oil level closely at start-up. If oil level is below the sight glass and cannot be seen, add oil until the level is approximately 1/4 of sight glass. See Carrier Standard Service Techniques, Refriger- ants section, for procedures to add or remove oil.

Fig. 31 Ð Shipping Brackets; 48 Series 054-074 Units and 50 Series Horizontal Discharge 054-074 Units

Table 8 Ð Oil Charge

UNIT SIZE	OIL CHARGE (pints)
034	16	( 8 each circuit)
044	28	(14 each circuit)
054	33	(19 ckt 1, 14 ckt 2)
064	38	(19 each circuit)
074	38	(19 each circuit)

NP034-074 specifications

The Carrier NP034-074 is an advanced rooftop unit designed for commercial heating, ventilation, and air conditioning (HVAC) applications. This unit is part of Carrier’s extensive range of rooftop units that are known for their energy efficiency, reliability, and innovative features. The NP034-074 series is particularly recognized for its robust performance in diverse environmental conditions, making it ideal for a variety of commercial building types.

One of the standout features of the NP034-074 is its high-efficiency compressor. Equipped with a scroll compressor, the unit offers enhanced performance and quieter operation compared to traditional reciprocating compressors. This design not only improves energy efficiency but also reduces operating costs over time. The unit is designed to meet or exceed the latest efficiency standards, ensuring that businesses can enjoy optimal indoor comfort while keeping energy consumption low.

The NP034-074 also integrates advanced control technologies that provide users with greater flexibility and ease of operation. The intuitive control system allows for precise temperature management and can be easily integrated with building automation systems. This enables users to monitor and adjust settings remotely, ensuring consistent and efficient climate control throughout the facility.

Another key characteristic of the NP034-074 is its robust construction. Built to withstand various weather conditions, the unit features a galvanized steel cabinet with a powder-coated finish for corrosion resistance. Its design also facilitates easy access for maintenance and service, which minimizes downtime and operational interruptions.

In terms of air distribution, the NP034-074 incorporates a powerful blower system that ensures even and effective airflow throughout the space. This design improves indoor air quality by enhancing ventilation while maintaining comfort levels. Additionally, the unit can be customized with options such as economizers and variable speed fans to optimize performance based on specific building needs.

The NP034-074 is a versatile and reliable choice for businesses looking to enhance their HVAC systems. With its combination of energy efficiency, advanced technology, and robust construction, this rooftop unit stands out as a top choice for commercial climate control solutions.