Daikin MicroTech III DPS Installation And Maintenance Manual page 52

Table 35: Standard Initialization Sequence, 16–28 Tons
Device
Inverter Compressor & Comp3
Inverter Compressor Only
Outdoor Fan
4 Way Valve (Heat Pump)
Indoor Coil
Expansion Valve (EVI)
Time Duration
A . Inverter compressor speed is increasing until the 4-way valve is seated (discharge minus suction pressure is >57 psi) and
as long as the suction pressure is above 43 psi . Comp3 remains OFF
B . Outdoor fan capacity is controlled to maintain the discharge pressure between 256 psi and 313 psi . Outdoor fan capacity
is set to 100% if discharge pressure is above 384 psi . Outdoor fan capacity runs at least at minimum capcity if heat sink
temperature is > 167°F
C . The indoor expansion vavle is to keep the suction superheat between 7 .2°F and 12 .0 °F
D . The standard initialization lasts a max of 120 seconds. It is completed early anywhere between 20 and 120 seconds if the
saturation suction temperature is high (above 118°F), the suction pressure is low (below 79 psi) or once the 4-way valve is
seated (differential pressure above 57 psi, suction below 142 psi, suction superheat above 27°F, and discharge superheat
above 34°F)
OM 1263 • MICROTECH UNIT CONTROLLER
Step 1
Inverter Compressor Speed = Inverter Compressor Speed =
Minimum
Comp3 = Off
If OAT ≥50°F or RAT ≥73°F,
Inverter Compressor Speed =
Inverter Compressor Speed = Smaller of Step 12 or Maximum
Minimum If OAT <50°F or RAT <73°F,
Inverter Compressor Speed =
Outdoor Fan = 0% if OAT <
68°F
Outdoor Fan = 5% if OAT ≥
68°F
OFF
C
5 Seconds
Step 2
Inverter Compressor Speed
= Increasing 2 steps every 5
Step 2
seconds if PTD-PTD < 26 PSI
Comp3 = Off
Comp3 = Off
Minimum
B
←
←
E = 25/28 Ton size
5 Seconds
5 Seconds ≠ 25/28 Ton size
52
Operator's Guide
Step 3 Step 4
Inverter Compressor Speed
= Increasing 1 step every 20
seconds if there is no change
of 4 Way Valve call
Comp3 = Off
←
←
←
←
www .DaikinApplied .com
A
←
←
←
D