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2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
4. Recovering Refrigerant
4-2-3. Refrigerant recovery procedures (2): (Indoor unit with no ball valve equipped)
Perform work correctly, according to the work procedures given below.
Refrigerant in all indoor units and the refrigerant tubing circuit must be pumped into the outdoor unit.
The maximum refrigerant storage capacity per a single outdoor unit is approx. 529 ~ 705 oz (15 ~ 20k
g
).
Thus, in order to collect all refrigerant from the system, a separate refrigerant recovery unit is necessary.
Follow these procedures to correctly perform pump down.
(1) Connect the manifold gauge to the high- and low-pressure outlet ports on the outdoor unit where pump down
will be performed. Be sure that no air enters the tubing at this time.
(2) Follow the instructions in “4-2-1. Cooling operation (for all units)” and operate all units in Cooling mode for
approximately 5 minutes. Then fully close the liquid tube valve on the outdoor unit where pump down will be
performed.
(4) Turn off power to all equipment in the system. Then pull out the RC1 connector (3P) (BLU) (CN75) on the outdoor
control PCB in the outdoor unit for which pump down has been completed.
(3) When the high-pressure gauge reaches 406.1 psi (2.8 MPa) or higher, or the low-pressure gauge reaches
72.5 psi (0.5MPa) or below, at the outdoor unit where pump down is being performed, press the ON/OFF button
on the outdoor unit maintenance remote controller to stop operation at all units. Then immediately fully close the
gas tube valve on the outdoor unit where pump down is being performed.
* By pulling out the RC1 connector, communication between the main and the sub outdoor units will be isolated.
* When not using the outdoor unit maintenance remote controller, short-circuit the STOP pin (CN28).
(5) Change the setting of controllable outdoor unit numbers (reduce by 1 unit).
(6) Turn on power for all equipment in the system and let the remaining outdoor units run in Cooling mode.
(9) Use hoses to connect the manifold gauge valves, refrigerant recovery unit, and refrigerant recovery cylinder.
Quickly connect each part to prevent air from entering the tubing.
(10) Recover remaining refrigerant from the inter-unit tubing and indoor units using the refrigerant recovery unit.
(7) Repeat steps “(1)” and “(2)” and complete pump down for all outdoor units.
(8) Using hoses with Schrader-type push-to-release valves, connect the manifold gauge valves to the gas tube
service port and the liquid tube service port in the next outdoor unit to undergo pump down. (Figs. 5-a, 5-b)
* If the setting is incorrect, the E30 alarm (outdoor unit serial communication signal error) occurs and the unit
will not operate.
It is not necessary to recover the refrigerant from the balance tube.
Therefore do not operate the balance tube valve.
CAUTION
Remaining refrigerant in the system may cause internal pressure.
Check that each valve on the manifold gauge is tightly closed.
A Schrader-type push-to-release valve is provided for each connection port.
CAUTION
NOTE
To determine the completion of refrigerant recovery, follow the instructions that came with the refrigerant
recovery unit.
4. Recovering Refrigerant
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
4. Recovering Refrigerant
Lo
Hi
Refrigerant
recovery unit
Manifold
gauge
Refrigerant recovery cylinder
(1) Turn off power to the entire outdoor system.
(3) If any unit has encountered a power failure, follow the instructions in “4-1. Refrigerant Recovery Procedures
(from Outdoor Units)” and perform refrigerant recovery for the faulty outdoor unit.
(4) Connect the manifold gauge to the high- and low-pressure outlet ports (Schrader-type valves) on any outdoor
unit. (Figs. 5-a, 5-b)
* If only a single outdoor unit is installed, the balance tube is not used. Therefore, leave this valve closed.
(5) Connect the manifold gauge valves, refrigerant recovery unit, and refrigerant recovery cylinder. Quickly connect
each part to prevent air from entering the tubing.
(6) Check that each service valve of the gas tubes, liquid tube, and the balance tube for the outdoor unit has opened,
then perform refrigerant recovery.
(2) Short-circuit the AP pin (CN24) on the outdoor control PCB of all outdoor units, then supply power to the
outdoor units.
* By short-circuiting the AP pin (CN24) and supplying power to the outdoor units, the solenoid valve in each
unit is forcibly opened and all remaining refrigerant can be recovered.
Remaining refrigerant may cause internal pressure.
Check that each valve on the manifold gauge valves is tightly closed.
The connection port uses a Schrader-type push-to-release valve.
CAUTION
NOTE
To determine the completion of refrigerant recovery, follow the instructions that came with the
refrigerant recovery unit.
Fig. 5-b
Fig. 5-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)
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)
Type: 72, 96
Lo
Hi
Refrigerant
recovery unit
Manifold
gauge
Refrigerant recovery cylinder
Type: 120, 144
4-3. Recovery of Refrigerant from Entire System
SM830237-07_北米向け2WAY_VRF.indb 13
18/06/18 18:48:12
