Checking For Leakage After Repair - Panasonic U-72MF2U9 Service Manual

5. Checking for Leakage After Repair

5. Checking for Leakage After Repair
5-1. Pressure Check for Leakage of Outdoor Unit
After completing repair of the outdoor unit, carry out the following leakage check.
(1) Check that all service valves for suction tube, discharge tube, liquid tube, and balance tube in the repaired
outdoor unit (units necessary to carry out the pressurized leak check) are fully closed.
(2) Connect the manifold gauge valves to the high- and low-pressure outlet ports of the outdoor unit.
(3) Feed nitrogen gas into the circuit until 484 psi (3.34 MPa) pressure is reached. If it is apparent that the nitrogen
gas is not entering the repaired section, interrupt the feeding. Short-circuit the AP pin (CN24) on the outdoor
unit control PCB, turn on power to run the outdoor unit, then resume feeding nitrogen.
(4) Apply soapy water to the repaired part (such as a newly brazed part), and briefly inspect for any leakage.
If there are any leaks, bubbles will show on the tubing surface.
* To continue the air-tight check after the brief leak inspection, turn on power while short-circuiting the AP
1
pin (CN24).
Again feed nitrogen gas to obtain a system pressure of 484 psi (3.34 MPa). Then measure both the outdoor
ambient temperature and the pressure in the system. Leave the system in this state for 1 full day and night,
and again measure the outdoor ambient temperature and pressure (to determine any reduced values).
During the inspection, it is recommended that an awning or cover be used to shield the unit in case of rain.
2
If no problem is found, purge all nitrogen from the system.
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4
5
6
7
8
5-2. Checking for Leakage in Refrigerant Tube Between Indoor and Outdoor Units
Refer to the "Installation Instructions" that came with the outdoor unit.
9
Type: 72, 96
Manifold
gauge
Lo Hi
Type: 120, 144
Manifold
gauge
Lo Hi
2 - 12
2WAY VRF SYSTEM
3WAY VRF SYSTEM
Outdoor Unit Repair Procedures
Outdoor Unit Repair Procedures
Low-pressure outlet port
(for ø5/16" (ø7.94mm)-dia connector)
High-pressure outlet port
(for ø5/16" (ø7.94mm)-dia connector)
Oil balance tube service port
(For ø5/16" (ø7.94mm)-dia connector)
Liquid tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Discharge tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Suction tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Fig. 6-a
Low-pressure outlet port
(for ø5/16" (ø7.94mm)-dia connector)
High-pressure outlet port
(for ø5/16" (ø7.94mm)-dia connector)
Oil balance tube service port
(For ø5/16" (ø7.94mm)-dia connector)
Liquid tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Suction tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Discharge tube service port
(for ø5/16" (ø7.94mm)-dia connector)
Fig. 6-b