Liebert DS user manual Fan Speed Charging, Fan speed suction pressure transducer settings

Piping

Fan Speed Charging

1.Check unit nameplate for refrigerant type to be used. Unit control configurations differ depending on refrigerant type.

2.Refrigerant charging requires unit operation. Refer to 10.0 - Checklist for Completed Installation.

3.Calculate the amount of charge for the system. Refer to the unit, condenser and refrigerant line charge data in Tables 46, 47 and 48.

4.Weigh in as much of the system charge as possible before starting the unit.

! CAUTION

Risk of improper refrigerant charging. Can cause equipment damage.

Refrigerant R407C is a blend of three components and must be introduced and charged from the cylinder only as a liquid.

When adding liquid refrigerant to an operating system, it may be necessary to add the refrigerant through the compressor suction service valve. Care must be exercised to avoid damage to the compressor. Emerson recommends connecting a sight glass between the charging hose and the compressor suction service valve. This will permit adjustment of the cylinder hand valve so that liquid can leave the cylinder while allowing vapor to enter the compressor.

5.Turn on unit disconnect switch. Operate the unit for 30 minutes using the charging function for System #1 and System #2 in the diagnostic section of the iCOM control (see iCOM user manual, SL-18835). The charging function operates the compressor at full capacity and energizes the blower motor and the liquid line solenoid valve. The reheat and humidifier are disabled. A minimum 20psig (138kPa) must be established and maintained for the compressor to operate. The charging function can be reset as many times as required to complete unit charging.

Table 49 Fan speed suction pressure transducer settings

	R-22		R-407C
	Gauge (Sea Level)	Absolute	Gauge (Sea Level)	Absolute
Function
	psiG (kPa)	psiA (kPa)	psiG (kPa)	psiA (kPa)
Pump-Down Cutout	20 (138)	35 (241)	20 (138)	35 (241)
Pump-Down Reset	65 (448)	80 (552)	65 (448)	80 (552)
Minimum to Start-Cooling	35 (241)	50 (344)	35 (241)	50 (344)
Low-Pressure Cutout (DX only)	48 (331)	63 (434)	52 (358)	67 (461)

6.Charge the unit until the liquid line sight glass becomes clear. Then add one additional pound (2.2kg) of refrigerant.

NOTE

A digital scroll compressor will have a clear sight glass only when operating at 100% capacity. When operating below 100%, the sight glass may show bubbles with each 15-second unloading cycle.

7.As head pressure builds, the fan speed controlled condenser fan begins rotating. The fan will run at full speed when sufficient head pressure is developed—fan starts to rotate at 190 psig (1310 kPA) and is full speed at 250 psig (1724 kPA).

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