How To Operate System While Failed Outdoor Unit Being Repaired - Toshiba MMY-MAP0724HT6UL 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 "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 114 type outdoor unit is under repair in a 228 type system:
Amount of refrigerant required by system as it was initially (228 type) = 78.3 lb (34.5 kg)
Amount of refrigerant required by system with available outdoor units only (114 type) = 40.8 lb (26.0 kg)
Amount of refrigerant to be removed from system = 78.3 (34.5) – 40.8 (26.0) = 37.5 lb (8.5 kg)
(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
capacity type
072 type
096 type
114 type
144 type
168 type
192 type
228 type
Combined outdoor units
072 type
096 type
114 type
072 type 072 type
096 type 072 type
096 type 096 type
114 type 114 type
191
Amount of
refrigerant
(lb (Kg))
– 28.7 (13.0)
– 38.6 (17.5)
– 40.8 (18.5)
50.7 (23.0)
67.2 (30.5)
78.3 (35.5)
78.3 (35.5)