78
Installation and Commissioning Guide 500-700 Tri-Capacity Split Ducted
Doc. No.0525-098 Ver. 2 210330
Installation and Commissioning Guide
Split Tri-Capacity
4. Start the unit in cool mode ensuring that both circuit compressors are in 100% operation before taking
service gauges reading. Allow the system to stabilise for next 20 minutes before recording.
Record the discharge pressure, suction pressure, liquid line temperature and suction line temperature for both
systems.
Circuit 1 System (Small Compressor) Circuit 2 System (Large Compressor)
Discharge Pressure = ________________ kPa Discharge Pressure = ________________ kPa
Suction Pressure = __________________ kPa Suction Pressure = __________________ kPa
Liquid Line Temperature (LLT) = ________
o
C Liquid Line Temperature (LLT) = ________
o
C
Suction Line Temperature (SLT) = _______
o
C Suction Line Temperature (SLT) = _______
o
C
NOTES
Accurate pressure and temperature measuring tools should be used to achieve satisfactory results. The sensors
of thermocouple must be in good contact with the area being measured and must be insulated in order to obtain
correct reading.
28.01.02. Checking For Subcooling
1. From the R-410A Pressure/Temperature Chart record the corresponding Saturated Condensing
Temperature (SCT) at the given discharge pressure.
2. Calculate the system subcooling using the formula below:
Subcooling = SCT - LLT
3. If subcooling is within the range 4-8K, there is no need to add/remove refrigerant.
• If subcooling is lower than 4K, the system is undercharged, it is necessary to add refrigerant.
• If subcooling is higher than 8K, the system is overcharged. It is necessary to remove refrigerant.
Allow the systems to stabilise and repeat the step 1-3 until subcooling falls within 4-8K.
28.01.03. Checking for Superheat
Maintaining the correct superheat is important for ensuring the evaporator is achieving maximum capacity and
avoiding excessive liquid refrigerant returning to the compressor.
1. From the R-410A Pressure/Temperature Chart record the corresponding Saturated Suction Temperature
(SST) at the given suction pressure.
2. Calculate the system super heat using the formula below:
Superheat = SLT -SST
3. If superheat is within the range 2-8K, there is no need to add/remove refrigerant.
• If superheat is lower than 2K, it means that liquid refrigerant may be returning to compressor.
It is necessary to remove refrigerant or check TXV settings.
• If superheat is higher than 8K, it means that refrigeration capability of evaporator is not fully maximised.
It is necessary to add refrigerant charge or check TXV settings.
Allow the systems to stabilise and repeat the step 1-3 until superheat falls within 2-8K.
NOTE
The above recommendations are based on design conditions of 35
0
C DB (outdoor), air entering indoor at 27
o
C DB /
19
o
C WB (as per AS/NZS 3823.1.2).
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