Recovering Refrigerant - Panasonic U-72MF2U9 Service Manual

4. Recovering Refrigerant

4. Recovering Refrigerant
The following equipment and tools are required:
Jumper wire with clips, adjustable wrench, set of manifold gauge valves specially designed for refrigerant R410A
only, vacuum pump, refrigerant recovery unit, pre-purged refrigerant cylinder for recovery, flathead screwdriver, and
outdoor unit maintenance remote controller.
4-1. Refrigerant Recovery Procedures (from Outdoor Units)
(1) Turn off the power of the outdoor unit beforehand (at power mains).
(2) Fully close all the service valve of the outdoor unit.
(3) Connect the outdoor unit's high-pressure and low-pressure outlet ports with the Hi and Lo sides of the manifold
gauge valves using hoses. (Figs. 3-a, 3-b)
The remaining refrigerant in the faulty outdoor unit may create internal pressure.
Before connecting hoses, be sure to confirm that each of the manifold gauge valves is
CAUTION
tightly closed. Note that the connection ports employ Schrader-type push-to-release valves.
(4) Connect the manifold gauge valves, refrigerant recovery unit, and recovery cylinder using hoses.
To avoid the entry of air into the refrigerant tube, carry out this connection work carefully. (Figs. 3-a, 3-b)
For detailed procedures such as connecting the refrigerant recovery unit with the recovery
cylinder and methods used for recovery, follow the specific instructions that came with the
CAUTION
refrigerant recovery unit.
(5) Locate the AP pin (CN24) on the control PCB in the faulty outdoor unit and short them using the clips of
the jumper wire. Then restore electrical power to the outdoor unit.
By short-circuiting the AP pin (CN24), each solenoid valve in the outdoor unit is forcibly
CAUTION opened as soon as power comes on, which releases all remaining refrigerant
into the recovery cylinder.
Since neglecting this procedure may leave some refrigerant in the system, it is important
that you carry out this step.
(6) Carry out refrigerant recovery.
To determine the completion of refrigerant recovery, follow the instructions that CAUTION
CAUTION
came with the refrigerant recovery unit.
Refrigerant
recovery unit
Refrigerant recovery cylinder
Type: 72, 96
Manifold
gauge
Lo Hi
2 - 7
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. 3-a
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2
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