8–9 62-11785
Only a refrigerant cylinder containing R404A should be connected to this refrigeration unit in
order to pressurize the system. However, dry nitrogen may be used to increase pressure. Any
other gas or vapor will contaminate the system and require additional removal and evacuation.
Do not vapor charge R404A. Only liquid charging through the liquid line service valve is
acceptable.
3. Ensure that the operator message panel displays “RECOVER/LEAK CHK/EVAC MODE” during the pressurizing
and leak checking procedures. (Refer to
Section 5.2.5
.) If the control system switches to Charge Mode during
the process, switch it back to the “RECOVER/LEAK CHK/EVAC MODE”.
4. Pressurize the system 5 to 10 psig (0.3 to 0.7 bar) with refrigerant at the liquid line service valve.
Do not use a nitrogen cylinder without a pressure regulator. Cylinder pressure is approxi-
mately 2350 psig (159.9 bar). Do not use oxygen in or near a refrigerant system as an explosion
may occur. (See
Figure 8.15
).
5. Connect a cylinder of dry nitrogen. Use the dry nitrogen to increase the pressure as necessary 20 to 150 psig
(1.4 to 10.2 bar) to detect the leak. The larger the leak the less pressure is required. The smaller the leak, the
greater pressure is required.
6. The recommended procedure for finding leaks from a system is with an electronic leak detector. Checking joints
with soapsuds is satisfactory only for locating large leaks, or pinpointing small leaks once a general area has
been located.
7. Once leak checking is complete, remove the refrigerant/nitrogen vapor out of the system.
8. If no leaks are found the system is ready for evacuation. (Skip to Step 11.)
9. If any leaks are found they must be repaired before proceeding.
10. Repeat steps 4 - 9 as necessary.
11. Evacuate the system after all leaks are repaired. Refer to
Section 8.5.4
.
c. Leak Checking With Low Side Pumped Down
The low side of the system must be leak checked once it is closed and all repairs complete.
1. Ensure the unit will not start automatically by disabling any two way communication and placing the START/
RUN-OFF switch in the OFF position. Disconnect the high voltage source and lockout/tagout the receptacle.
Only a refrigerant cylinder containing R404A should be connected to this refrigeration unit in
order to pressurize the system. However, dry nitrogen may be used to increase pressure. Any
other gas or vapor will contaminate the system and require additional removal and evacuation.
2. Connect refrigerant system equipment if not already connected. Refer to
Figure 8.4
.
Do not vapor charge R404A. Only liquid charging through the liquid line service valve is
acceptable.
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