Start-Up, Preliminary Checks, Using Vacuum Pump

START-UP

Preliminary Checks

1.Check condensate drainage system; on the opposite side of the drain connection, insert a water bottle up into the fan coil unit and fill the drain pan. Water must flow steadily; if not, check the pipe slope or inspect for any pipe restrictions.

2.Make sure all wiring connections are correct and they are tight.

3.Field electrical power source must agree with unit name plate rating.

4.Check that all barriers, covers, and panels are in place. En- sure that the filters and return-air grilles on the indoor unit have been installed and that the discharge louvers are posi- tioned correctly.

5.All service valves must be closed.

6.On units with crankcase heaters, ensure belly-band heaters are tight around the compressor.

Evacuate and Dehydrate the System

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

Never use the system compressor as a vacuum pump.

Using Vacuum Pump

1.Completely tighten flare nuts A, B, C, D, connect manifold gage charge hose to a charge port of the low side service valve. (See Fig. 34.)

2.Connect charge hose to vacuum pump.

3.Fully open the low side of manifold gage. (See Fig. 35)

4.Start vacuum pump

5.Evacuate using either deep vacuum or triple evacuation method.

6.After evacuation is complete, fully close the low side of manifold gage and stop operation of vacuum pump.

7.The factory charge contained in the outdoor unit is good for up to 25 ft. (8 m) of line length. For refrigerant lines longer than 25 ft (8 m), add 0.3 oz. per foot of extra piping up to the maximum allowable length.

8.Disconnect charge hose from charge connection of the low side service valve.

9.Fully open service valves B and A.

10.Securely tighten caps of service valves.

Outdoor Unit

Refrigerant

Indoor Unit

A Low Side

B High Side

Service Valve

A07360

Fig. 34 - Service Valve

Manifold Gage
500 microns
Low side valve	High side valve
Charge hose	Charge hose
	Charge hose

Vacuum pump

Low side valve

A07361

Fig. 35 - Manifold

Deep Vacuum Method

The deep vacuum method requires a vacuum pump capable of pulling a vacuum of 500 microns and a vacuum gage capable of accurately measuring this vacuum depth. The deep vacuum method is the most positive way of assuring a system is free of air and liquid water. (See Fig. 36)

5000
4500
4000						LEAK IN
3500						LEAK IN
3500						SYSTEM
3000						SYSTEM
3000
2500
MICRONS2000						VACUUM TIGHT
1500						VACUUM TIGHT
1500						TOO WET
1000						TOO WET
1000						TIGHT
500						TIGHT
500						DRY SYSTEM
						DRY SYSTEM
0	1	2	3	4	5	6	7
			MINUTES
							A95424

Fig. 36 - Deep Vacuum Graph

40QNQ, 40QNC specifications

The Carrier 40QNC and 40QNQ are advanced rooftop packaged units designed for efficient heating and cooling in commercial applications. These units are particularly known for their reliability, versatility, and energy-efficient performance, making them a preferred choice for building owners and HVAC professionals alike.

One of the standout features of the Carrier 40QNC and 40QNQ units is their variable-speed technology. This innovative system allows for precise control of airflow and temperature, ensuring that indoor environments maintain consistent comfort levels while minimizing energy consumption. The variable-speed compressor operates at different speeds based on the cooling demand, leading to reduced energy costs and improved overall efficiency.

In terms of energy performance, both models boast high Seasonal Energy Efficiency Ratios (SEER) and Heating Seasonal Performance Factors (HSPF). This not only contributes to lower energy bills but also helps in meeting energy efficiency standards and regulations in various regions. This makes the 40QNC and 40QNQ ideal for environmentally conscious building projects aiming for sustainability.

Another notable feature is the advanced microchannel coil technology utilized in these units. Microchannel coils are lighter, more compact, and provide enhanced heat exchange capabilities compared to traditional coils. This technology contributes to a more efficient refrigerant flow and ultimately leads to improved performance and durability of the unit.

Moreover, both models come equipped with a robust control system that enhances user interface. With smart thermostat compatibility, users can easily manage their building's climate remotely, ensuring optimal comfort and energy management. These systems are designed to integrate seamlessly with building management systems (BMS), allowing for greater control and optimization.

The construction of the Carrier 40QNC and 40QNQ also deserves mention. The units are built with durable materials designed to withstand harsh weather conditions, providing longevity and reliability. Additionally, the low sound levels produced by these units make them suitable for noise-sensitive settings, ensuring comfort without disruptive operation.

In summary, the Carrier 40QNC and 40QNQ are exemplary rooftop packaged units that combine advanced technology, energy efficiency, and reliable performance. Their variable-speed operation, microchannel coil technology, and robust control systems make them ideal solutions for commercial heating and cooling needs, catering to both comfort and sustainability.