How To Operate System While Failed Outdoor Unit Being Repaired - Toshiba MMY-MAP0726FT2P-UL 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 troubled. 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 "11-1. 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 6 ton outdoor unit is under repair in a 12 ton system:
Amount of refrigerant required by system as it was initially (12 ton in capacity)=55.2 lbs
Amount of refrigerant required by system with available outdoor units only (6 ton in capacity)=28.7 lbs
Amount of refrigerant to be removed from system =55.2 - 28.7= 26.5 lbs
(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.
Outdoor unit Outdoor unit
capacity capacity type
(ton) (ton)
6 072 type
12 144 type
Combined outdoor units
Header Follower
Outdoor unit Outdoor unit1
072 type
072 type 072 type
Type
Standard Model
Standard Model
− 227 −
Adjustment amount of
refrigerant
(lbs)
28.7
55.2