70
OPERATION FOR CV
On CV units equipped with a VFD (staged air volume) when
SP.CF
,
SP.SV
, and
SP.S
are configured, the
Comfort
Link con-
trol will control the speed of the supply fan based on the oper-
ating mode of the unit. The VFD speed setting points are
SP.MN
,
SP.MX
. When in LOW COOL mode and the compres-
sor stage is less than 50%, fan will be at
SP.MN
minimum
speed. When greater than 50% capacity, the fan will be at
SP.MX
maximum speed. In VENT mode, the fan speed will be
at
SP.MN
minimum speed. In HEATING mode, the fan will
operate at 75% speed when the heating stage is 75% or less and
at 100% speed when the heating stage is greater than 75%. On
units configured for 2 stage thermostat operation, the fan will
be at 100% on a call for W2 and at 75% on a call for only W1.
SETTING UP THE SYSTEM
The options for static pressure control are found under the Lo-
cal Display Mode
Configuration
SP
. See Table 59.
Static Pressure Configuration (SP.CF)
This variable is used to configure the use of
Comfort
Link con-
trols for static pressure control.
When set to disable, there is no static pressure control by
Com-
fort
Link controls. This would be used for a constant volume
(CV) application when static pressure control is not required or
for a VAV application if there will be third-party control of the
VFD. In this latter case, a suitable means of control must be
field installed.
When set to enable, this will enable the use of
Comfort
Link con-
trols for static pressure control via a supply fan VFD. On CV
units with VFD, staged air volume, this must be set to disable.
Staged Air Volume Control (SP.SV)
This variable enabled the use of a CV unit with VFD for staged
air volume control.
Static Pressure Sensor (SP.S)
This variable enables the use of a supply duct static pressure
sensor. This must be enabled to use
Comfort
Link controls for
static pressure control. If using a third-party control for the
VFD or IGV, this should be disabled. Do not use when
SP.SV
is enabled.
Static Pressure Low Range (SP.LO)
This is the minimum static pressure that the sensor will mea-
sure. For most sensors, this will be 0 in. wg. The
Comfort
Link
controls will map this value to a 4 mA sensor input.
Static Pressure High Range (SP.HI)
This is the maximum static pressure that the sensor will mea-
sure. Commonly, this will be 5 in. wg. The
Comfort
Link con-
trols will map this value to a 20 mA sensor input.
Static Pressure Set Point (SP.SP)
This is the static pressure control point. It is the point against
which the
Comfort
Link controls compare the actual measured
supply duct pressure for determination of the error that is used
for PID control. Generally, one would set
SP.SP
to the mini-
mum value necessary for proper operation of air terminals in
the conditioned space at all load conditions. Too high of a val-
ue will cause unnecessary fan motor power consumption at
part-load conditions and/or noise problems. Too low a value
will result in insufficient airflow. Additional information will
be found on page 71, under Static Pressure Reset.
VFD Minimum Speed (SP.MN)
This is the minimum speed for the supply fan VFD. Typically,
the value is chosen to maintain a minimum level of ventilation.
NOTE: Most VFDs have a built-in minimum speed adjustment
which must be configured for 0% when using
Comfort
Link con-
trols for static pressure control. When
SP.SV
is enabled, the range
is 33 to 67% with the default setting of 67%.
VFD Maximum Speed (SP.MX)
This is the maximum speed for the supply fan VFD. This is
usually set to 100%.
VFD Fire Speed Override (SP.FS)
This is the speed that the supply fan VFD will use during the
fire modes; pressurization, evacuation and purge. This is usual-
ly set to 100%.
Static Pressure Reset Configuration (SP.RS)
This option is used to configure the static pressure reset func-
tion. When
SP.RS
= 0, there is no static pressure reset via an
analog input. When
SP.RS
= 1, there is static pressure reset
based on the CEM 4-20MA input and ranged from 0 to
3 in. wg. When
SP.RS
= 2, there is static pressure reset based
on RAT and defined by
SP.RT
and
SP.LM
. When
SP.RS
= 3,
there is static pressure reset based on SPT and defined by
SP.RT
and
SP.LM
. When
SP.RS
= 4, there is VFD speed con-
trol where 0 mA = 0% speed and 20 mA = 100% (
SP.MN
and
SP.MX
will override).
Static Pressure Reset Ratio (SP.RT)
This option defines the reset ratio in terms of static pressure
versus temperature. The reset ratio determines how much the
static pressure is reduced for every degree below set point for
RAT or SPT.
Table 59 — Static Pressure Control Configuration
ITEM
EXPANSION
RANGE
UNITS
CCN POINT
DEFAULT
SP
SUPPLY STATIC PRESS.CFG.
SP.CF
Static Pressure Config
Enable/Disable
STATICFG
Disable
SP.SV
Staged Air Volume Control
Enable/Disable
STGAVCFG
Disable
SP.S
Static Pressure Sensor
Enable/Disable
SPSENS
Disable
SP.LO
Static Press. Low Range
–10 to 0
in. W.C.
SP_LOW
0
SP.HI
Static Press. High Range
0 to 10
in. W.C.
SP_HIGH
5
SP.SP
Static Pressure Setpoint
0 to 5
in. W.C.
SPSP
1.5
SP.MN
VFD Minimum Speed
0 to 100
%
STATPMIN
20
SP.MX
VFD Maximum Speed
0 to 100
%
STATPMAX
100
SP.FS
VFD Fire Speed Over.
0 to 100
%
STATPFSO
100
SP.RS
Stat. Pres. Reset Config
0 to 4
SPRSTCFG
0
SP.RT
SP Reset Ratio (
/dF)
0 to 2.00
SPRRATIO
0.2
SP.LM
SP Reset Limit in iwc (
)
0 to 2.00
SPRLIMIT
0.75
SP.EC
SP Reset Econo.Position
0 to 100
%
ECONOSPR
5
S.PID
STAT.PRESS.PID CONFIGS
SP.TM
Static Press. PID Run Rate
5 to 120
sec
SPIDRATE
15
SP.P
Static Press. Prop. Gain
0 to 5
STATP_PG
0.5
SP.I
Static Pressure Intg. Gain
0 to 2
STATP_IG
0.5
SP.D
Static Pressure Derv. Gain
0 to 5
STATP_DG
0.3
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 ...