Mitsubishi Electric City Multi CMB-P1016NU-G, Service Handbook

Page: 173 / 349

- 164 -
[
VIII
Test Run Mode ]
[5] Refrigerant Amount Adjust Mode
1. Procedures <PQHY>
Follow the procedures below to add or extract refrigerant as necessary depending on the operation mode.
When the function switch switches (SW2-4) on the main board on the heat source unit are turned to ON, the unit will go into
the refrigerant amount adjust mode.
Notes:
1) There may be cases when the refrigerant amount may seem adequate for a short while after starting the unit in the
refrigerant amount adjust mode but turn out to be inadequate later on (when the refrigerant system stabilizes).
[When the amount of refrigerant is truly adequate.]
TH5-TH7 on the heat source unit is 5K[9°F] or above and SH on the indoor unit is between 5 and 15K[9 and 27°F].
[The refrigerant amount may seem adequate at the moment, but may turn out to be inadequate later on.]
TH5-TH7 on the heat source unit is 5K[9°F] or less and SH on the indoor unit is 5K[9°F] or less.
Wait until the TH5-TH7 reaches 5K[9°F] or above and the SH of the indoor unit is between 5 and 15K[9 and 27°F] to
determine that the refrigerant amount is adequate.
2) High pressure must be at least 2.0MPa[290psi] to enable a proper adjustment of refrigerant amount to be made.
3) Adjust the refrigerant amount based on the values of TH1, TH5, TH7, and Tc and by following the flow chart below.
TH1, TH5, TH7, and Tc can be displayed by setting the self-diagnosis switch (SW1) on the main board on the heat
source unit.
4) Refrigerant amount adjust mode automatically ends 90 minutes after beginning. When this happens, by turning off
the SW2-4 and turning them back on, the unit will go back into the refrigerant amount adjust mode.
Use these switches to figure out the values of TH1, TC - TH5, and Tc - H7.
Operation When the unit is in the refrigerant amount adjust mode, the LEV on the indoor unit does not
open as fully as it normally does during cooling operation to secure subcooling.
Self-diagnosis swithes on TH1
Self-diagnosis swithes on TH7
Self-diagnosis swithes on TH5
Self-diagnosis swithes on Tc
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
ON