Carrier MMY-MAP0724FT9UL Service Manual page 212

[Setup of the power cannot be turned on the failed outdoor unit]
If the power cannot be turned on the failed outdoor unit, the solenoid valves and PMVs of the unit cannot be
turned on, so that it reduces the amount of recovered refrigerant compared to a standard pump-down
operation. Recover the residual gas in the unit using a refrigerant recovery device, and be sure to measure the
amount of recovered refrigerant.
<Work procedure>
[Setup of failed outdoor unit]
(1) Connect the liquid pipe check joint and the low pressure-side check joint using a gauge manifold, and
purge the manifold of air (to recover refrigerant from the liquid tank and heat exchangers).
(2) Fully close the liquid pipe packed valve and service valve at discharge gas side of the failed outdoor unit.
(Leave the service valve of the suction gas pipe and the packed valve of the balance pipe fully open.)
[Setup of unit selected as header unit (hereafter "header outdoor unit")]
(3) Set SW01/02/03 on the interface P.C. board of the header outdoor unit to 2/5/1. After [C. ] [... ... ...] is
displayed on the 7-segment display, push SW04 and hold for 5 seconds or more.
(4) After [C. ...] [... – C] is displayed on the 7-segment display, the system starts operating in the test cooling
operation mode.
(5) Set SW01/02/03 on the interface P.C. board of the header outdoor unit to 1/2/2 to have the low-pressure
sensor output psi (MPa) displayed on the 7-segment display.
(1)
Connect liquid pipe check joint and
low pressure-side check joint using
gauge manifold, and purge manifold
of air.
(2)
Fully close liquid pipe service valve.
(Leave suction gas and balance
pipes fully open.)
(6) Approx. 10 minutes after the system starts up, fully close the suction gas pipe service valve of the failed
outdoor unit.
[Setup of outdoor unit for pressure adjustment]
(7) Select the header unit as the unit for pressure adjustment.
[Setup of header unit]
(8) While monitoring the low-pressure sensor output, adjust the pressure to around 17 psi (0.12 MPa) by slowly
closing the suction gas pipe service valve.
(9) Compare the manifold gauge pressure of the failed unit with the low-pressure sensor output of the header
unit, and wait until the two pressure readings become almost identical. After letting the system continue
operating for a while longer, fully close the suction gas pipe service valve of the unit for pressure
adjustment.
Failed outdoor unit
(3) Set SW01/02/03 to 2/5/1.
[C. ] [ ... ... ...] is displayed
↓
(4) Push SW04 and hold for 5 seconds or more.
[C. ...] [ ... − C] is displayed. (Test cooling
operation begins).
↓
(5) Push SW04 to display the low pressure psi (MPa)
Unit selected as header unit
Interface P.C. board
– 212 –