Refrigerant Leakage Detection - Toshiba MMY-MAP0726FT2P-UL Service Manual

8-7-11. Refrigerant leakage detection

The refrigerant leakage can be confirmed by using the switches on Interface PCB of
the outdoor unit.
If there is a leak, the location must be found in order to recover the refrigerant.
After that, implement appropriate countermeasure and refill the refrigerant to its
standard volume.
Refrigerant leaks can be detected by comparing the Actual opening of PMV with the Calculated
opening of PMV* during the operation.
* Calculated opening of PMV: calculated from the initial value(C.i/H.i), the pressure sensor value,
the compressor's rotation speed, and the opening of PMV. The initial values are automatically
saved when the specified conditions are met.
(A leak can be detected only when C.i/H.i = 1)
[Operation]
(1) Confirming the refrigerant leakage
Set SW01 to 03 as shown in the following table to confirm whether the leaks are being detected.
(It also can be confirmed by remote control monitor function. Refer to "8-7-12. Monitor function of remote
controller switch.)
(2) Clearing the initial value
If the system is changed (e.g. indoor units are increased/replaced, outdoor units are moved, or refrigerant is
refilled/increased) it is necessary to clear the initial value that had been saved.
Make sure that the compressor has stopped, and then press and hold SW04 for at least 5 seconds.
SW01 SW02 SW03
2 13 14
(3) Checking the record of the initial value
Set SW01 to 03 as shown in the following table to confirm the record of the initial value.
SW01 SW02 SW03
2 14 14
2 15 14
[Clear]
Return SW01/SW02/SW03 on the Interface PCB in the outdoor unit to [1/1/1] .
NOTE)
(a) During the operation, the slow leaks can be detected.
However, if the air-conditioner cannot cooling down / cannot warming up / make an unusual stop, the
slow leaks might not be detectable. The fast leaks always cannot be detected.
(b) Poor refrigerant circulation may be detected as a refrigerant leaks.
(e.g. plugged strainers / capillaries, malfunction / clogging of the PMV / 2-way valve / 4-way valve)
(c) Due to the outside temperature, the initial value may not be recorded, or it may be impossible to determine
the leakage.
(d) The initial value cannot be saved until the accumulated operating time has reached at least 20 hours.
(e) The initial value cannot be saved if the indoor unit's operating ratio is low.
(f) If the following indoor units are connected, leakage determination is not possible.
・ Air to air heat exchanger with DX coil unit
Refrigerant leakage detection
Cooling initial value
Heating initial value
Display detail
A [ L. d ]
B Normal: [ ... ... 0]
Possibility of leakage: [... ... 1]
Clear the data: [...C.L] (Only Display for 5 seconds)
Display detail
A [ C. i ]
B Incomplete: [... ... 0]
Completed: [... ... 1]
A [ H. i ]
B Incomplete: [... ... 0]
Completed: [... ... 1]
− 130 −