Daikin VRV II RXYQ5MATL, Service Manual

Page: 86 / 331

Si39-504 Basic Control
Function 75
2.3 Electronic Expansion Valve PI Control
Main Motorized Valve EV1 Control
Carries out the motorized valve (Y1E) PI control to maintain the evaporator outlet superheated
degree (SH) at constant during heating operation to make maximum use of the outdoor unit
heat exchanger (evaporator).
The optimum initial value of the evaporator outlet superheated degree is 5°C, but varies
depending on the discharge pipe superheated degree of inverter compressor.
Subcooling Motorized Valve EV2 Control
Makes PI control of the motorized valve (Y2E) to keep the superheated degree of the outlet gas
pipe on the evaporator side for the full use of the subcooling heat exchanger.
2.4 Step Control of Outdoor Unit Fans
Used to control the revolutions of outdoor unit fans in the steps listed in table below, according to condition changes.
*
Figures listed above are all those controlled while in standard mode, which vary when the system is set to high static
pressure or capacity precedence mode.
SH = Ts - Te SH : Evaporator outlet superheated degree (°C)
Ts : Suction pipe temperature detected by
thermistor R2T (°C)
Te : Low pressure equivalent saturation
temperature (°C)
SH = Tsh -Te SH : Outlet superheated degree of evaporator (
°
C)
Tsh : Suction pipe temperature detected with the
thermistor R5T (
°
C)
Te : Low pressure equivalent saturation
temperature (
°
C)
STEP
No.
Fan revolutions (rpm)
RXYQ5MA RXYQ8MA RXYQ10MA RXYQ12MA RXYQ14MA RXYQ16MA
0 0 0 0 0 0 0
1 300 300 300 300 300 300
2 320 320 320 325 325 325
3 350 345 345 355 355 355
4 385 385 385 400 400 400
5 470 465 465 500 500 500
6 585 575 575 605 605 605
7 800 765 785 880 880 880
8 840 825 825 920 920 920