Liebert Extreme Density Chiller XDC - Manual (Page 36)

Piping and Filling with Refrigerant: R-134a and R-407c Circuits
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2.6.1 Air Cooled Condenser with Lee-Temp “Flooded Condenser” Head Pressure Control
System—R-407c (DX) Circuit
The Lee-Temp system consists of a modulating type head pressure control valves and insulated
receivers with heater pads to ensure operation at ambient temperatures as low as -30°F (-34.4°C).
Lee-Temp Piping
Two discharge lines and two liquid lines must be field-installed between the indoor unit and the out-
door condenser. See Figures 24 and 27 for details.
Lee-Temp Control Materials Supplied
• Built-in, pre-wired condenser control box
• Air cooled condenser
• Piping access cover to be reinstalled when piping is complete
• Bolts—four per leg (3/8" x 5/8")
• Terminal block for two-wire, 24V interlock connection between unit and condenser
• Condensate legs—four with one-fan, six on two-and three-fan models and eight on four-fan mod-
els
• Bolts—used to mount receiver (3/8" x 1-1/4")
• Lee-Temp system:
• Insulated storage receiver—one per circuit
• Head pressure control assembly (head pressure valves and check valves) - one per circuit
• Service valve—one per circuit
• Pressure relief valve—one per circuit
• Liquid level sight glasses
Evacuation and Leak Check—R-407c (DX) Circuit (Air and Water/Glycol Systems)
1. Make sure the unit is Off. Open all disconnects and pull all fuses except the control fuses. On
units supplied with circuit breakers, open all breakers except for the transformer.
2. Energize the liquid line solenoid valves via 24VAC or through Diagnostics under “Test Outputs,”
select DEHYDRATION to be On (see 5.3.17 - DIAGNOSTICS). This will energize the solenoids
and hot gas valves to open simultaneously on Circuit 1 and Circuit 2.
3. Attach refrigerant gauges to the suction and discharge service valves of the compressor.
4. Open all compressor service valves, including those located outside the Liebert XDC.
5. Connect the tank of dry nitrogen to the Schrader valves on the liquid lines and the hot gas lines.
6. Pressurize the system circuit(s) to 150 PSIG (1034 kPa; 10.34 bars) with dry nitrogen with a trace
of refrigerant. Check the system for leaks with a suitable leak finder.
7. After completion of leak testing, release the test pressure (per local code) and connect to vacuum
pump(s) at the Schrader valves on the liquid lines and on the hot gas lines.
8. After 4 hours of pulling a deep vacuum, check the vacuum levels and, if they have not changed,
break the vacuum with dry nitrogen.
9. Pull a second and third vacuum to 250 microns or less. Recheck the vacuum level after 2 hours.
NOTE
Lee-Temp heater pads require a separate, continuous electrical source. See nameplate on unit
for proper voltage.
NOTE
The procedures above allow the technician to use 24VAC power and controls to open liquid line
solenoid valve(s) for the dehydration process. If no power is at the unit disconnect, the
technician is to use a separate 24VAC source rated at 75 VA and connect to the system liquid
line solenoid valve(s) directly.