Emerson Xtreme Density manual Liebert XDC DX R-407c Circuit Volume-Air Cooled Units

Designing a Liebert XD Solution

3.16.2Calculating Refrigerant Charge—Example

Using Tables 7, 8, 9 and 10, calculate the refrigerant charge of the individual sections of your Liebert XD system. Add the calculated charge amounts to determine the amount of R-134a refrigerant required for one system combining a Liebert XDP with Liebert XD cooling modules (Liebert XDCF, Liebert XDH, Liebert XDO and Liebert XDV). The example below combines one Liebert XDP with 20 Liebert XDV8 cooling modules.

Table 11 Calculating refrigerant charge—example

	Number of Units
Components	or Piping Length, feet	Pounds Per Component	Total, lb.
Liebert XDP/Liebert XDC	1	157	157
Liebert XDV8 Cooling Modules	20	2.32	46.4
Supply Main, 1-1/8"	100	0.45	45
Return Main, 2-1/8"	100	0.28	28
Liebert XDV 1/2" supply Flex	20	0.8	16
Pipes
Liebert XDV 5/8" return Flex	20	0.03	0.6
Pipes
		Total	293

Table 12 Worksheet to calculate refrigerant charge

Components

Number of Units or Piping Length

Pounds Per Component

Total

Total

Verify that the refrigerant volume of the Liebert XD system with the longest piping length is within the allowable limit. If the allowable limit is exceeded, the Liebert XDP/Liebert XDC should be moved closer to the cooling modules (refer to 3.12 - Liebert XD Refrigerant for limits and related details). Another way to shorten the total pipe length is to reroute the pipe runs.

3.17Liebert XDC DX R-407c Circuit Volume—Air Cooled Units

! CAUTION

Risk of improper lubrication. May cause equipment damage.

Liebert XDCs with refrigerant R-407c charges over 35 lb. (15.9kg) require additional oil. Refer to the Liebert XDC user manual, SL-16671, available at Liebert’s Web site, www.liebert.com

Weigh in the calculated charge based on Tables 13, 14 and 15.

Table 13 Indoor unit refrigerant charge—R-407c

Model 60/50 Hz	Charge/Circuit, lb. (kg)
Liebert XDC160	17.5 (8.0)

28