2
- 9
1
2
3
4
5
6
7
8
9
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
(2) Adjusting the refrigerant for backup operation
During backup operation, all of the service valves on the failed unit are closed. However, if a check of the backup
operating conditions shows that the level of gas is low, recover the refrigerant from the failed outdoor unit.
If the level of gas is too high, collect refrigerant at the failed outdoor unit.
After recovery work is completed, wire the communication lines between indoor and outdoor
units again. If it not finished yet, an alarm is emitted immediately.
CAUTION
Recovering refrigerant
With the normal outdoor units operating, monitor the operating condition and open/close the gas tube service
valve on the failed outdoor unit where all the service valves were closed.
In this way, recover refrigerant from the failed outdoor unit in order to adjust the amount of refrigerant in the
system. After adjusting the amount of refrigerant, close the gas tube valve at the failed outdoor unit.
Collecting refrigerant in the failed outdoor unit
Short-circuit the AP pin (CN24) on the control PCB of the failed outdoor unit where the service valves are
closed, then turn the power ON. Also disconnect the wiring between the outdoor units.
With the normal outdoor units operating, monitor the operating condition and open/close the liquid tube
service valve on the failed outdoor unit where all the service valves were closed.
In this way, collect refrigerant in the failed outdoor unit in order to adjust the amount of refrigerant in the
system.
After adjusting the amount of refrigerant, turn OFF the power at the failed outdoor unit, release the short-
circuit at the AP pin (CN24), and close the liquid tube valve at the failed outdoor unit.
* Refrigerant recovery is not affected by the power status of the failed outdoor unit. However, collecting
refrigerant in the failed outdoor unit is affected by whether the power at that outdoor unit can be turned
ON. If the power cannot be turned ON, use a refrigerant recovery device and recover the refrigerant into
a recovery cylinder in order to adjust the amount of refrigerant in the system.
3. Backup Operation
4. Recovering Refrigerant
4-1. Refrigerant Recovery Procedures (from Outdoor Units)
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.
(1) Turn off the power of the outdoor unit beforehand (at power mains).
(2) Fully close each service valve on the liquid tube, gas tubes, and the balance tube 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)
(4) Connect the manifold gauge valves, refrigerant recovery unit, and recovery cylinder using hoses.
To avoid the entry of air into the refrigerant tubing, carry out this connection work carefully. (Figs. 3-a, 3-b)
(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.
(6) Carry out refrigerant recovery.
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
4. Recovering Refrigerant
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
tightly closed. Note that the connection ports employ Schrader-type push-to-release valves.
CAUTION
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
refrigerant recovery unit.
CAUTION
By short-circuiting the AP pin (CN24), each solenoid valve in the outdoor unit
is forcibly 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.
CAUTION
To determine the completion of refrigerant recovery, follow the instructions that CAUTION
came with the refrigerant recovery unit.
CAUTION
Type: 72, 96
Fig. 3-a
High-pressure outlet port
(for ø5/16” (ø7.94mm)-dia connector)
Low-pressure outlet port
(for ø5/16” (ø7.94mm)-dia connector)
Liquid tube service port
(for ø5/16” (ø7.94mm)-dia connector)
Gas tube service port
(for ø5/16” (ø7.94mm)-dia connector)
Lo
Hi
Refrigerant
recovery unit
Manifold
gauge
Refrigerant recovery cylinder
SM830237-07_北米向け2WAY_VRF.indb 9
18/06/18 18:48:10
