Evacuating System - Panasonic U-10MF1E8 Service Manual

7. Evacuating System

This procedure is carried out to ensure there is no remaining refrigerant or other gases (nitrogen, etc.) in the
repaired outdoor unit and tubing.
7-1. Evacuating Repaired Outdoor Unit
(1) Check that each service valve of the suction tube, discharge tube, liquid tube, and balance tube in the outdoor
unit are fully closed.
(2) Connect the manifold gauge valves to the high-pressure and low-pressure sensor outlets of the outdoor unit.
(Fig. 11)
(3) Connect the manifold gauge valves to the vacuum pump.
* If the AP pins (CN102) on the outdoor control PCB have already been short-circuited, step (4) is not
necessary.
(4) Turn off power to the repaired outdoor unit and short-circuit the AP (Air Purge) pins on the outdoor control PCB.
By short-circuiting the AP pins and turning on power to the outdoor unit, all
CAUTION
electronic valves in the outdoor unit are forcibly opened and any remaining
nitrogen gas can be recovered. Failure to perform this procedure may result in
nitrogen gas remaining in the refrigerant circuit and causing operating problems.
Therefore, never skip this step.
(5) Turn the power ON at the outdoor unit where vacuum will be applied. Then run the vacuum pump and continue
evacuation until the vacuum condition falls to less than –101 kPa (–755 mmHg, 5 Torr).
To ensure proper evacuation, refer to the operating instructions that came with the
CAUTION
vacuum pump.
Vacuum pump
7-2. Evacuating Refrigerant Tubing Between Indoor and Outdoor Units
Refer to the "Installation Instructions" that came with the outdoor unit.
Manifold gauge
Lo Hi
High-pressure outlet port
(For 7.94mm-dia. connector)
Fig. 11
2 - 15
3-WAY SYSTEM
Outdoor Unit Repair Procedures
Low-pressure outlet port
(For 7.94mm-dia. connector)
2