Variable 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 2.9 - 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 6, 7, 8 and 9.
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 the system in the diagnostic section of the Liebert iCOM control (see Liebert iCOM user manual,
Table 10 Fan speed suction pressure transducer settings
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| ||
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|
| |
| Gauge (Sea Level) |
| Absolute |
Function |
|
|
|
psiG (kPa) |
| psiA (kPa) | |
|
|
|
|
20 (138) |
| 35 (241) | |
|
|
|
|
65 (448) |
| 80 (552) | |
|
|
|
|
Minimum to | 35 (241) |
| 50 (344) |
|
|
|
|
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
7.As head pressure builds, the variable fan speed controlled condenser fan begins rotating. The fan will run at full speed when sufficient head pressure is
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