Evacuating System - Panasonic U-8MF2E8 Service Manual

6. 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.
6-1. Evacuating Repaired Outdoor Unit
(1) Check that each service valve of the gas tubes, 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. 7)
(3) Connect the manifold gauge valves to the vacuum pump.
* If the AP pins (CN24) 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.
CAUTION
(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 –101kPa (–755 mmHg, 5 Torr).
CAUTION
Low-pressure outlet port
(for ø7.94mm-dia connector)
Vacuum pump
By short-circuiting the AP pins and turning on power to the outdoor unit, all elec-
tronic 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.
To ensure proper evacuation, refer to the operating instructions that came with
the vacuum pump.
Manifold
gauge
Lo Hi
Outdoor Unit Repair Procedures
Fig. 7
2 - 13
3WAY SYSTEM
Oil balance tube service port
(For 7.94mm-dia. connector)
High-pressure outlet port
(for ø7.94mm-dia connector)
Liquid tube service port
(for ø7.94mm-dia connector)
Discharge tube service port
(for ø7.94mm-dia connector)
Suction tube service port
(for ø7.94mm-dia connector)
2