How To Operate System While Failed Outdoor Unit Being Repaired - Carrier MMY-MAP0724FT9UL Service Manual

11-2. 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 096 type outdoor unit is under repair in a 216 type system:
Amount of refrigerant required by system as it was initially (216 type in capacity) = 82.6 lb
Amount of refrigerant required by system with available outdoor units only (120 type in capacity) = 51.8 lb
Amount of refrigerant to be removed from system = 82.6 – 51.8 = 30.8 lb
(3) Set up the outdoor unit from which refrigerant has been recovered in the manner described in "10-3.
Outdoor Unit
Backup Operation Setting".
This completes the procedure.
Outdoor unit
conbined outdoor units
capacity type
072 type 072 type
096 type 096 type
120 type 120 type
144 type 072 type
168 type 096 type
192 type 096 type
216 type 120 type
240 type 120 type
Amount of refrigerant
[ lbs (kg) ]
— 30.9 (14.0)
— 46.3 (21.0)
— 52.9 (24.0)
072 type 56.2 (25.5)
072 type 73.9 (33.5)
096 type 81.6 (37.0)
096 type 84.9 (38.5)
120 type 88.2 (40.0)
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