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10-2.How to Operate System While Failed Outdoor Unit
Being Repaired
<Outline>
After refrigerant is recovered from the failed outdoor unit through a pump-down operation, the overall amount of
refrigerant held by the system becomes excessive, and this makes it impossible to operate the remaining outdoor
units even though they are not faulty. However, operation is still possible if the system-wide amount of refrigerant
is adjusted in accordance with the procedure described below.
<Work procedure>
(1) Follow the steps specified in “10-1. Refrigerant Recovery from Failed Outdoor Unit (Pump-Down)”.
(2) Adjust the amount of refrigerant held by the system by removing some of it using a refrigerant recovery device,
etc.
Determine the amount of refrigerant to be removed according to the capacity of the failed outdoor unit. (See the
table below.)
Example:
If a 10HP outdoor unit is under repair in a 30HP system:
Amount of refrigerant required by system as it was initially (30HP in capacity) = 34.5kg
Amount of refrigerant required by system with available outdoor units only (20HP in capacity) = 26.0kg
Amount of refrigerant to be removed from system = 34.5 – 26.0 = 8.5kg
(3) Set up the outdoor unit from which refrigerant has been recovered in the manner described in “9-3. Outdoor Unit
Backup Operation Setting”.
This completes the procedure.
System capacity (HP)
Outdoor unit combination
Amount of refrigerant (kg)
8
8
13.0
10
10
14.0
12
12
15.0
14
14
20.0
16
8
8
23.0
16
22.0
18
8
10
23.0
20
10
10
26.0
22
10
12
28.0
24
8
8
8
30.5
12
12
30.5
26
8
8
10
30.5
10
16
30.5
28
8
10
10
32.5
12
16
32.5
30
10
10
10
34.5
14
16
34.5
32
8
8
8
8
40.0
16
16
35.5
34
8
8
8
10
40.0
10
12
12
37.5
36
8
8
10
10
40.0
12
12
12
38.5
38
8
10
10
10
40.0
10
12
16
40.5
40
10
140
10
10
41.0
12
12
16
41.5
42
10
10
10
12
42.0
12
14
16
42.5
44
10
10
12
12
44.0
12
16
16
44.5
46
10
12
12
12
46.0
14
16
16
46.5
48
12
12
12
12
48.0
16
16
16
48.5
