Table 62: Alternate Initialization Sequence
Device Step 1 Step 2 Step 3
Inverter Compressor & Comp 3
Inverter Compressor Speed=Minimum
Comp3=Off
Inverter Compressor Speed=Smaller of Step 12 or Maximum
Comp3=Off
A
Inverter Compressor Only Inverter Compressor Speed= Minimum
If OAT≥50°F or RAT≥73°F, Inverter Compressor Speed=Smaller of Step
12 or Maximum
If OAT<50°F & RAT<73°F, Inverter Compressor Speed= Minimum
A
Outdoor Fan Outdoor Fan=0% B ←
4 Way Valve
(Heat Pump only)
OFF ← ←
Outdoor Coil
Expansion Valve (EVO)
(Heat Pump only)
EVO=100% ← ←
SVR (Heat Pump only) Closed ← ←
SVB
Normally Open
Close if Discharge superheat>9°F
← ←
Indoor Coil Expansion Valve (EVI) EVI= 0% C ←
Time Duration 5 seconds 5 seconds D
A. Inverter compressor speed is increased until the 4-way valve is seated (discharge minus suction pressure >57 psi) and as
long as the suction pressure is above 43 psi. inverter compressor speed is also increased if the suction pressure remains
above 71 psi. Comp 3 turns on if the inverter compressor speed is at maximum and these conditions are not met. Comp 3
is turned back OFF after 20 seconds if the suction pressure drops 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 capacity if inverter board
(n) temperature >167°F.
C. EVI is controlled to keep the suction superheat between 3.6°F and 14.4°F.
D. Alternate Initialization lasts a maximum 15 minutes. It is completed early anywhere between 10 seconds and 15 minutes if
once the 4-way valve is seated (differential pressure above 57 psi and the discharge superheat above 9.0°F).
OM 1141-3 • MICROTECH UNIT CONTROLLER 88 www.DaikinApplied.com
operator’s guIde
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