Daikin MicroTech III DPS Installation And Maintenance Manual page 54

Table 37: Alternate 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 . Inverter compressor speed is increased if the suction pressure remains
above 71 psi . Comp3 turns ON if the inverter compressor speed is at maximum and these conditions are not met . Comp3 is
turned back OFF afer 20 seconds if the suction pressure is below 43 psi
B . Outdoor fan capacity is controlled to maintain the discharge pressure between 171 psi and 221 psi . Outdoor fan capacity
is set to 100% if discharge pressure is above 427 psi . Outdoor fan capacity runs at least at minimum capcity if heat sink
temperature is >167°F
C . The indoor expansion valve is to keep the suction superheat between 7 .2°F and 20°F
D . The standard initialization lasts a max of 15 minutes. It is completed early anywhere between 20 and 15 minutes if the
4-way valve is seated (differential pressure above 57 psi and discharge superheat above 34°F)
E . Step 3 ends when the compressor has reached 65% full speed, differential pressure is >26 psi for 3 seconds, the stage has
been active for 3 minutes, or Comp3 is active
F . Step 4 (initializaiton) is complete when the stage has been active for 15 minutes, or 4-way valve has set and discharge
superheat is above 34°F
OM 1263 • MICROTECH UNIT CONTROLLER
Step 1
Inverter Compressor Speed =
Minimum
Comp3 = Off
Inverter Compressor Speed =
Minimum
Outdoor Fan = 0% if OAT < 68°F
Outdoor Fan = 5% if OAT ≥ 68°F
OFF
EVI = 0%
5 Seconds
Step 2
Inverter Compressor Speed =
Step 2
seconds if PTD-PTD < 26 PSI
Comp3 = Off
If OAT ≥50°F or RAT ≥73°F,
Inverter Compressor Speed =
Smaller of Step 12 or Maximum
If OAT <50°F or RAT <73°F,
Inverter Compressor Speed =
Minimum
B
←
C
5 Seconds
54
Operator's Guide
Step 3
Inverter Compressor Speed
= Increasing 1 step every 5
Comp3 = Off
A
←
←
←
E = 25/28 Ton size
D ≠ 15 Ton size
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Step 4
A
N/A
←
←
←
F