Service manual
Service Manual SM-MDS_(i)      59 
5.8 Start All Indoors 
After confirming that the MDS system is ready in standby mode without any faulty operation or error code, turn 
on all indoor units one by one. This can be done through the commissioning software or manually turn on each 
indoor unit individually. Set the indoor temperature according to the design requirement. There are a few things 
which we need to check for outdoor and indoor: 
Outdoor checking 
• Check the compressor status (ON/OFF and its running capacity) as it should react 
according to the system’s need. 
•  Check the high side (HS) and low side (LS) pressure to ensure they do not exceed the 
designed limit. 
•  Check the readings of discharge temperature sensor (TH1) and ensure it do not 
exceed the designed limit. 
•  Check the opening of EXV4 and subcool temperature (TH9 – TH10) for cooling mode. 
•  Check is there any error code from the outdoor unit. 
Indoor checking 
•  Check the handset’s functionality for each indoor such as setting swing mode and see 
whether or not the indoor unit is responding towards the handset’s signal. 
•  Check the readings of indoor temperature sensor (T
i
, T
m
, T
o
 and T
r
) and ensure they 
are normal. 
•  Check the opening of the EXV box and ensure it is functioning normally. 
•  Check is there any error code from the indoor unit. 
5.9 Monitor Outdoor Parameter 
After the commissioning personnel added in the additional refrigerant, it is advisable that they monitor the 
outdoor parameter. In order to guide the commissioning personnel, the factory side had provided a set of outdoor 
parameter for reference. There are 3 sets of reference data provided (3 sets for cooling cycle and 3 sets for 
heating cycle). 
These data will serve as a guide on the possible operating condition of the unit. Once the outdoor parameter 
reach or close to the proposed data, the charging of the refrigerant can be stop. The commissioning personnel 
will need to continue to monitor the outdoor parameter for some time (1/2 to 1 hour). If the outdoor parameters 
remain constant or very small movement, the commissioning can be concluded. 
For details, kindly refer to the following Appendix for the required model. 
•  Appendix 7.7 - R22 MDS A Series Cooling Cycle Reference 
•  Appendix 7.8 - R22 MDS B Series Cooling Cycle Reference 
•  Appendix 7.9 - R22 MDS A Series Heating Cycle Reference 
•  Appendix 7.10 - R22 MDS B Series Heating Cycle Reference 
•  Appendix 7.11 - R410A MDS B Series Cooling Cycle Reference 
•  Appendix 7.12 - R410A MDS B Series Heating Cycle Reference 
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