Emerson PFH020A-L, User Manual

Page: 28 / 117

Site Preparation and Installation
21 Liebert
®
Mini-Mate2
™
Split System, Air-Cooled Model Refrigerant (R-407C) Loop
All split systems require two refrigerant lines—an insulated copper suction line and a copper liquid
line—between the evaporator and the outdoor condensing unit.
The refrigerant lines can be piped by installing:
• an optional sweat adapter kit and hard piping between the two units.
• optional pre-charged line sets (maximum combined length of 45' [13.7m]).
All refrigeration piping should be installed with high-temperature brazed joints. Prevailing good
refrigeration practices should be employed for piping supports, leak testing, evacuation, dehydration
and charging of the refrigeration circuits. The refrigeration piping should be isolated from the
building with vibration-isolating supports. To prevent tube damage when sealing openings in walls
and to reduce vibration transmission, use a soft, flexible material to pack around the tubes.
NOTICE
Risk of twisted or kinked piping. Can cause flow restriction or leaks.
Handle the pre-charged lines with care so they do not get kinked or damaged. Use tube
benders and make all bends before making connections to either end. Coil any excess tubing
in a horizontal plane with the slope of the tubing toward the condensing unit.
Field-Fabricated Piping
All field-fabricated refrigeration piping should use copper pipe with high-temperature brazed joints.
A brazing alloy with a minimum temperature of 1350°F (732°C), such as Sil-Fos. Avoid soft solders
such as 50/50 or 95/5.
1. Use sweat adapter kit matched to the Liebert Mini-Mate2 and outdoor condensing unit
refrigerant connection sizes.
2. Measure pipe runs and calculate pipe size and equivalent feet of suction and liquid lines per
Tables 5 and 8 .
3. Use a flow of dry nitrogen through the piping during brazing to prevent formation of copper oxide
scale inside the piping. Copper oxide forms when copper is heated in the presence of air. POE oil
will dissolve these oxides from inside the copper pipes and deposit them throughout the system,
clogging filter driers and affecting other system components. A pure dry nitrogen flow of
1-3 ft 3 /min (0.5-1.5 l/s) inside the pipe during brazing is sufficient to displace the air. Control the
flow using a suitable metering device.
4. Pressurize and leak-test the completed lines at approximately 150 psig (1034kPa) pressure.
5. Evacuate each line twice to 250 microns. Break the vacuum each time with clean, dry nitrogen.
6. Evacuate the lines a third time to 250 microns.
7. See
Quick-Connect Fittings on page 24 for the proper procedure to connect lines to each unit
of the split system.
8. Add refrigerant (R-407C) to the completed system as calculated per Table 7 for both liquid and
suction line sizes used.
When installing remote condensing units above the evaporator, the suction gas line should be trapped
at the evaporator. This trap will retain refrigerant oil during the Off cycle. When the unit starts, oil in
the trap is carried up the vertical riser and returns to the compressor (see Figure 11 ).
!
WARNING
Risk of explosive discharge from high-pressure refrigerant. Can cause injury or death.
This unit contains fluids and gases under high pressure. Relieve pressure before working with
piping.