Panasonic U-20ME1E81, Service Manual

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3 - 15
2WAY SYSTEM
Outdoor Unit Repair Procedures
3
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 gas tubes, 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 3.8 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 pins (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 pins.
Again feed nitrogen gas to obtain a system pressure of 3.8 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. If no problem
is found, purge all nitrogen from the system.
High-pressure outlet port
(for ø7.94mm-dia connector)
Low-pressure outlet port
(for ø7.94mm-dia connector)
Gas tube service port
(for ø7.94mm-dia connector)
Type 8HP / 10HP / 12HP
Nitrogen gas
Lo Hi
Manifold gauge
Liquid tube service port
(for ø7.94mm-dia connector)
Fig. 6-a
SM830204-05_2WAY SYS_new.indb 15 15/01/05 15:31:32