Pumpdown; Standby For Restart - Daikin MicroTech III DPS Installation And Maintenance Manual

Pumpdown

Compressor heating operation enters the Pumpdown state before entering the Standby for Restart state from either the
Initialization or Normal Heating state.
The following describes the operation of the compressor heating control devices in the Pumpdown state:
Table 46: Pumpdown State
4 Way Valve (4WV)
Outdoor Expansion Valve (EVO)
Indoor Expansion Valve (EVI)
A . Pumpdown is complete after 3 minutes or when the suction pressure drops below 34 psi . Pumpdown is terminated if either
the discharge superheat rises above 230°F or if the Inverter Compressor port temperature rises above 284°F .

Standby for Restart

The Standby for Restart state guarantees at least one Htg Stg Time period elapses before re-entering the Intializaton and Normal
Heating states. The following describes the Standby for Restart state sequence:
Table 47: Standby for Restart State
Compressors
Outdoor Fan
4 Way Valve (4WV)
Outdoor Expansion Valve (EVO)
SVR
SVB
Indoor Expansion Valve (EVI)
Time Duration
OM 1263 • MICROTECH UNIT CONTROLLER
Compressors
Outdoor Fan
SVR
SVB
Time Duration
Inverter Compressor speed = 0%
Outdoor Fan speed = 50% if OAT > 86°F when
entering Standby for Restart state
Outdoor Fan speed = 0% if OAT ≤ 86°F when entering
Outdoor Expansion Valve position = 0%
Indoor Expansion Valve position = 0%
Inverter Compressor Speed = Smaller of Step 12 or maximum
Outdoor Expansion Valve position = 0%
Indoor Expansion Valve Control position = 50%
Step 1
Comp3=OFF
Standby for Restart state
ON
Closed
Closed
5 seconds
Htg Stg Time (default = 5 minutes)
66
Step 1
Comp3=OFF
Outdoor Fan speed = maximum
ON
Closed
Open
See A below
Step 2
←
←
←
←
Closed
←
←
Remainder of Htg Stg Time
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Heat Pump