Evacuating System - Panasonic U-120ME2U9 Service Manual

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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.

(Figs. 7-a, 7-b)

(3) Connect the manifold gauge valves to the vacuum pump.

* If the AP pin (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 pin (CN24) 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 –14.7 psig { -101 kPa, 5 Torr }.

CAUTION

Vacuum pump

6-2. Evacuating Refrigerant Tubing Between Indoor and Outdoor Units

Refer to the "Installation Instructions" that came with the outdoor unit.

By short-circuiting the AP pin (CN24) and turning on power to the outdoor unit, all

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.

To ensure proper evacuation, refer to the operating instructions that came with the

vacuum pump.

Type: 72, 96

Manifold

gauge

Type: 120, 144

Manifold

gauge

2 - 15

2WAY VRF SYSTEM

Outdoor Unit Repair Procedures

Low-pressure outlet port