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(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 di-
rectly by the
Comfort
Link controls. There is no physical Mo-
tormaster 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 56 for more information.
Maximum Condenser Temp (SCT.H)
This configuration defines the saturated condensing tempera-
ture at which the head pressure control routine will increase an
outdoor fan stage. The saturated condensing temperature of ei-
ther 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 tempera-
ture 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 outdoor fan staging will occur, and the outdoor
fan stage will default to the maximum stage.
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 com-
pressor 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
digital scroll capacity adjustments.
Dig Scroll Reduce Delta (DS.RP)
This configuration defines the maximum capacity the digital
scroll will be allowed to decrease per request by the SUMZ
Cooling Algorithm when OAT is greater than
Configuration
COOL
DS.RO
. This ramped reduction is only imposed on a
decrease in digital scroll capacity. An increase in capacity will
continue to follow the value defined by
Configuration
COOL
DS.AP
.
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
COOL
DS.RO
. This ramped
reduction is only imposed on a decrease in digital scroll capac-
ity. An increase in capacity will continue to follow the value
defined by
Configuration
COOL
DS.AD
.
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
COOL
DS.RP
) and time de-
lay (
Configuration
COOL
DS.RD
) will be imposed on a
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
COOL
DS.AP
and
Configuration
COOL
DS.AD
.
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
digital scroll will be locked at 100% above this outdoor-air
temperature.
Min Load Valve Enable (MLV)
This configuration instructs the control as to whether a mini-
mum load valve has been installed and will be controlled by
the compressor staging routine.
High SST Alert Delay Time (H.SST)
This option allows the low saturated suction temperature alert
timing delay to be adjusted.
Reverse Rotation Verified? (RR.VF)
This configuration is used to enable or disable the compressor
reverse 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
assumption that there will be a drop in suction pressure upon a
compressor 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:
• 5 seconds prior to compressor start.
• At the instant the compressor starts.
• 5 seconds after the compressor starts.
The rate of suction pressure change from 5 seconds prior to
compressor start to compressor start (rate prior) is compared to
the rate of suction pressure change from compressor start to 5
seconds after 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
require a manual reset.
It is important to note that in Service Test mode, reverse rota-
tion is checked on every compressor start.
Once it has been verified that power to the unit and compres-
sors has been applied correctly and the compressors start up
normally, this configuration can be set to YES to disable the re-
verse rotation check.
Use CSBs for HPS detect? (CS.HP)
On units with multiple compressors running on a circuit, the
current sensor boards (CSBs) are used to help detect a high
pressure switch trip. Setting this configuration to NO disables
this additional high pressure switch trip detection.
COOL MODE SELECTION PROCESS
The P Series
Comfort
Link controls offer three distinct methods
by which they may select a cooling mode.
1. Thermostat (
C.TYP
=3): The thermostat does not depend
upon the state of occupancy or temperature and the modes
are called out directly by the discrete inputs (
Inputs
STAT
Y1
and
Y2
).
2. VAV cooling types (
C.TYP
=1 and 2) are called out in the
occupied period (
Operating Modes
MODE
OCC
=ON).
3. VAV cooling types (
C.TYP
=1 and 2) are called out in the
unoccupied period (
Operating Modes
MODE
OCC
=
OFF). They are also used for space sensor control types
(
C.TYP
=4) in both the occupied and unoccupied periods.
This section is devoted to the process of cooling mode determi-
nation for the three types outlined above.
Summary of Contents for Weathermaster 48P2030-100
Page 130: ...130 Fig 19 Typical Power Schematic Sizes 040 075 Shown ...
Page 131: ...131 Fig 20 Main Base Board Input Output Connections ...
Page 132: ...132 Fig 21 RXB EXB CEM SCB Input Output Connections ...
Page 133: ...133 Fig 22 Typical Gas Heat Unit Control Wiring 48P030 100 Units Shown ...
Page 134: ...134 Fig 23 Typical Electric Heat Wiring 50P030 100 Units Shown ...
Page 135: ...135 Fig 24 Typical Power Wiring 115 V ...
Page 136: ...136 Fig 25 Typical Gas Heat Section Size 030 050 Units Shown ...
Page 138: ...138 Fig 27 Component Arrangement Size 030 035 Units ...
Page 139: ...139 Fig 28 Component Arrangement Size 040 075 Units ...
Page 140: ...140 Fig 29 Component Arrangement Size 090 100 Units ...