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This configuration must be set to 1 (CIRCUIT A) for size 30 to
60 units if an accessory low ambient operation Motormaster
control is installed on the unit.
If the unit is configured for the Humidi-MiZer adaptive dehumidi-
fication system, then circuit B automatically becomes the lead
circuit when the unit enters into one of the Humidi-MiZer modes
(dehumidification or reheat). The unit will immediately start a cir-
cuit B compressor when a Humidi-MiZer mode is initiated.
MotorMaster Control? (M.M.)
The condenser fan staging control for the unit is managed directly
by the ComfortLink controls. There is no physical Motormaster
device in the standard unit. This configuration must be set to YES
if an accessory low ambient operation Motormaster V Control is
installed on the unit. Setting this configuration to YES alters the
condenser fan staging sequence to accommodate the Motormaster
V control. See the Head Pressure Control section on page 58 for
more information.
Maximum Condenser Temp (SCT.H)
This configuration defines the saturated condensing temperature at
which the head pressure control routine will increase an outdoor
fan stage. The saturated condensing temperature of either running
circuit rising above this temperature will increase a fan stage. If
the outdoor-air temperature is greater than 72°F, then no outdoor
fan staging will occur, and the outdoor fan stage will default to the
maximum stage.
Minimum Condenser Temp (SCT.L)
This configuration defines the saturated condensing temperature at
which the head pressure control routine will decrease an outdoor
fan stage. The saturated condensing temperature of both running
circuits decreasing below this temperature will decrease a fan
stage. If the outdoor-air temperature is greater than 72°F, no out-
door fan staging will occur, and the outdoor fan stage will default
to the maximum stage.
Outdoor Fan VFD Enable (OV.EN)
The optional Greenspeed
®
/low ambient control configuration
units with additional outdoor fan speed control option is installed
from the factory. For the unit with Greenspeed/low ambient option
installed, the Outdoor VFD (Configuration
configuration needs to be set to YES to fully utilize the function of
the optional head pressure control for improving energy efficien-
cies or extended operational ambient conditions. See the Head
Pressure Control section on page 58 for more information.
Low Ambient Set Point (LASP)
This is the head pressure setpoint used by the ComfortLink control
during condenser fan staging and maintaining head pressure con-
trol for unit with Greenspeed/low ambient option. This configura-
tion will have a range of 70 to 150°F and have a default of 100°F.
A1 is Digital Scroll (DG.A1)
This configuration instructs the unit controls as to whether the A1
compressor is a digital scroll or regular scroll compressor. If set to
YES, the compressor will be controlled by the compressor staging
routine and SUMZ Cooling Algorithm.
A1 Min Digital Capacity (MC.A1)
This configuration defines the minimum capacity the digital scroll
compressor is allowed to modulate to. The digital scroll compres-
sor modulation range will be limited from MC.A1 to 100%.
Dig Scroll Adjust Delta (DS.AP)
This configuration defines the maximum capacity the digital scroll
will be allowed to change per request by the SUMZ Cooling
Algorithm.
Dig Scroll Adjust Delay (DS.AD)
This configuration defines the time delay in seconds between digi-
tal scroll capacity adjustments.
Dig Scroll Reduce Delta (DS.RP)
®
V
This configuration defines the maximum capacity the digital scroll
will be allowed to decrease per request by the SUMZ Cooling Al-
gorithm when OAT is greater than Configuration
DS.RO. This ramped reduction is only imposed on a decrease in
digital scroll capacity. An increase in capacity will continue to fol-
low the value defined by Configuration
Dig Scroll Reduce Delay (DS.RD)
This configuration defines the time delay, in seconds, between
digital scroll capacity reduction adjustments when OAT is greater
than Configuration
only imposed on a decrease in digital scroll capacity. An increase
in capacity will continue to follow the value defined by Configu-
ration
Dig Scroll Reduction OAT (DS.RO)
Under certain operating conditions, a sharp decrease in digital
scroll capacity can result in unstable unit operation. This config-
uration defines the outdoor air temperature above which a re-
duced capacity (Configuration
lay (Configuration
digital scroll capacity reduction. This ramped reduction is only
imposed on a decrease in digital scroll capacity. An increase in
capacity will continue to follow the values defined by Configu-
ration
Dig Scroll Max Only OAT (DS.MO)
This configuration defines the outdoor air temperature above
which the digital scroll will not be allowed to modulate. The digi-
tal scroll will lock at 100% above this outdoor-air temperature.
Min Load Valve Enable (MLV)
This configuration instructs the control as to whether a minimum
load valve has been installed and will be controlled by the com-
pressor staging routine.
High SST Alert Delay Time (H.SST)
This option allows the low saturated suction temperature alert tim-
ing delay to be adjusted.
Reverse Rotation Verified? (RR.VF)
COOL
OV.EN)
This configuration is used to enable or disable the compressor re-
verse rotation detection algorithm. This algorithm performs a
check for correct compressor rotation upon power up of the unit.
The method for detecting correct rotation is based on the assump-
tion that there will be a drop in suction pressure upon a compres-
sor start if it is rotating in the correct direction.
A test is made once, on power up, for suction pressure change on
the first compressor of the first circuit to start.
Reverse rotation is determined by measuring suction pressure at 3
points in time:
•
•
•
The rate of suction pressure change from 5 seconds prior to com-
pressor start to compressor start (rate prior) is compared to the rate
of suction pressure change from compressor start to 5 seconds af-
ter compressor start (rate after).
If (rate after) is less than (rate prior minus 1.25), alarm A140 is
generated. This alarm will disable mechanical cooling and will re-
quire a manual reset.
It is important to note that in Service Test mode, reverse rotation is
checked on every compressor start.
Once it has been verified that power to the unit and compressors
has been applied correctly and the compressors start up normally,
this configuration can be set to YES to disable the reverse rotation
check.
52
COOL
DS.RO. This ramped reduction is
COOL
DS.AD.
COOL
DS.RD) will be imposed on a
COOL
DS.AP and Configuration
5 seconds prior to compressor start.
At the instant the compressor starts.
5 seconds after the compressor starts.
COOL
COOL
DS.AP.
COOL
DS.RP) and time de-
COOL
DS.AD.
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Troubleshooting
