Daikin J Series Service Manual download pdf (Page 120)

SiE18-201 System control

Main Functions 109

3.29 Gas Pipe Isothermal Control in Cooling Operation

Purpose of the

Function

This function ensures appropriate refrigerant distribution when many room units are operating in

the cooling mode.

Outline The gas pipe temperatures of operating room units are detected by the gas pipe thermistors,

and the motorized valves' flow rates are corrected so as to equalize the temperatures of the gas

pipes.

When gas pipe temperature is higher than average → Opens the valve of that room unit

When gas pipe temperature is lower than average → Closes the valve of that room unit

However, the closing operation is restricted to prevent the valve operation that results in a flow

rate that exceeds a certain level at one time.

(Protection function to prevent rotor frosting)

Details The gas pipe temperature is detected at every sampling (40 SEC) operation of the gas pipe

isothermal control, and average value DGAV of each gas pipe temperature is obtained.

In order to prevent dew condensation in the connection pipe, when DGAV < Gas pipe lower limit

temp., DGAV = Gas pipe lower limit temp.

Gas pipe lower limit temp. = 0.2 ° DOA + 1

-20 0 20 40 60

Outside air temperature

Gas pipe lower-limit temperature

(M1048)

1 2 ... 115 116 117 118 119 120 121 122 123 124 125 ... 343 344

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Daikin J Series Service Manual Page 120