Allied Air Enterprises 4HP16LT manual Cooling Cycle, Charge Using Weigh-InMethod

Cooling Cycle

OUTDOOR UNIT

DEFROST THERMOSTAT

EXPANSION/CHECK VALVE

LOW HIGH PRESSURE PRESSURE

GAUGE MANIFOLD

TO LIQUID

R410A LINE

DRUM SERVICE

PORT

DISTRIBUTOR		NOTE - ARROWS INDICATE
			DIRECTION OF
	REVERSING VALVE		REFRIGERANT FLOW
OUTDOOR COIL
BIFLOW			INDOOR UNIT
FILTER / DRIER
MUFFLER
SUCTION	SUCTION
SERVICE
	LINE
PORT
	VALVE
COMPRESSOR
	EXPANSION/CHECK VALVE		INDOOR
			COIL

Use gauge ports on suction line valve and liquid line valve for evacuating refrigerant lines and indoor coil. Use suction gauge port to measure suction pressure during charging.

Figure 12

•Low pressure gauge to suction line service valve

•High pressure gauge to liquid line service valve

2.Close manifold gauge set valves. Connect the center manifold hose to an upright cylinder of R410A.

3.If room temperature is below 70°F, set the room thermo- stat to call for heat. This will create the necessary load for properly charging the system in the cooling cycle.

4.Use a digital thermometer to record the outdoor ambient temperature.

5.When the heating demand has been satisfied, switch the thermostat to cooling mode with a set point of 68°F. When pressures have stabilized, use a digital thermom- eter to record the liquid and suction line temperatures.

6.The outdoor temperature will determine which charg- ing method to use. Proceed with the appropriate charging method.

Charge Using Weigh-In Method

If the system is void of refrigerant, or if the outdoor ambient temperature is cool, first locate and repair any leaks then use the weigh-in method to charge the unit.

1.Recover the refrigerant from the unit.

2.Conduct a leak check, then evacuate as previously outlined.

3.Weigh in the charge according to the total amount shown on the unit nameplate.

If weighing facilities are not available, use one of the following procedures to charge the unit.

Charge Using Subcooling Method –

Outdoor Temperatures Below 65°F

When the outdoor ambient temperature is below 65°F, the subcooling method can be used to charge the unit. It may be necessary to restrict the air flow through the outdoor coil to achieve pressures in the 200-250 psig range. These higher pressures are necessary for checking the charge. Block equal sections of air intake panels and move obstructions sideways until the liquid pressure is in the 200-250 psig range (see Figure 13 on page 14).

1.With the manifold gauge hose still on the liquid service port and the unit operating stably, use a digital thermometer to check the liquid line temperature. For best results, use the same digital thermometer to check both the outdoor ambient and the liquid line temperatures.

2.At the same time, record the liquid line pressure reading.

3.Use the temperature/pressure chart (Table 5 on page 14) to determine the saturation temperature for the liquid line pressure reading.

506468-01 Issue 1004 Page 13