VCC-X SETPOINTS
VCC-X Operator Interface SD
44
Setpoint Screen #12 - Outdoor Dewpoint
Setpoint
VCC-X Spts ID:#
Outdoor Dewpoint
Setpoint: 55.0
º
F
On MUA con
fi
gured units (100% or high percentage Outdoor Air
units), or if this is a unit in Hood On MUA operation, Dehumidi
fi
ca-
tion will be initiated if the Outdoor Air Dewpoint rises 2°F above
this setpoint. If the humidity falls 2°F below this setpoint, the unit
will leave the Dehumidi
fi
cation Mode.
Description
Minimum
Default
Maximum
Outdoor Dewpoint
Setpoint
35ºF
(1.7
º
C)
55ºF
(12.8ºC)
80ºF
(26.6ºC)
Setpoint Screen #13 - Indoor RH Setpoint
Disable/Low Reset and Enable/High Reset
Source
VCC-X Spts ID:#
Indoor RH Setpoint
Disable/Lo Rst: 50%
Enable/Hi Rst: 60%
This screen is used to set the Indoor Humidity Setpoints and the
Space Humidity Reset range used to reset the Coil Suction Tem-
perature Setpoint.
On units where Indoor Humidity is used to initiate Dehumidi
fi
cation
(non MUA units), the unit will enter Dehumidi
fi
cation as the Indoor
Humidity rises above the Enable/High Reset Source (Hi Rst Src)
Setpoint and will leave Dehumidi
fi
cation as the Indoor Humidity
falls below the Disable/Low Reset Source (Lo Rst Scr) Setpoint.
The Indoor Humidity Setpoint range con
fi
gured on this screen also
establishes the Indoor Humidity range that will be used to reset
the Coil Suction (Saturation) Temperature Setpoint between the
High Reset Limit (HiRst Lmt) and the Low Reset Limit (Lo Rst
Lmt) con
fi
gured on the next screen. If not reset is desired the Coil
Temperature Setpoints on the following screen should both be set
to the same value.
The following two paragraphs will describe the reset function.
If no reset of the Coil Suction (Saturation) Temperature Setpoint is
desired, then on
Setpoint Screen #14
set the Coil Temperature High
Reset Limit the same as the Coil Temperature Low Reset Limit.
On MUA units, where the Outdoor Dewpoint Setpoint is used to
initiate Dehumidi
fi
cation, this screen is only used to set the Indoor
Humidity values that will reset the Coil Suction (Saturation) Tem-
perature Setpoint – if reset is desired. See the 3rd paragraph above
for the description of how to set this up.
VCC-X Setpoint Screens
Description
Minimum
Default
Maximum
Indoor RH Setpoint
Disable/Low Reset
Source
0%
50%
100%
Indoor RH Setpoint
Enable/High Reset
Source
0%
60%
100%
Setpoint Screen #14 - Coil (Saturation)
Temperature Low & High Reset Limits
VCC-X Spts ID:#
Coil Temp Setpoint
Hi Rst Lmt: 45
º
F
Lo Rst Lmt: 40
º
F
Based on the Indoor Humidity Reset Range con
fi
gured on the pre-
vious screen, the Coil Suction (Saturation) Temperature Setpoint
can be reset between the High Reset Limit (Hi Rst Lmt) and Low
Reset Limit (Lo Rst Lmt) con
fi
gured on this screen during the
Dehumidi
fi
cation Mode. See the description of this reset function
on the previous screen. If the High Reset Limit and the Low Reset
Limit are set at the same value, no Coil Temperature Reset will occur.
Description
Minimum
Default
Maximum
Coil Temp Setpoint
High Reset Limit
35ºF
(1.7
º
C)
45ºF
(7.2
º
C)
70ºF
(21.1
º
C)
Coil Temp Setpoint
Lo Reset Limit
35ºF
(1.7
º
C)
40ºF
(4.5
º
C)
70ºF
(21.1
º
C)
Setpoint Screen #15 - Static Pressure
Setpoint & Deadband
VCC-X Spts ID:#
Static Pressure
Setpoint: 1.50”
Deadband: 0.10”
For VAV units, a Supply Fan VFD or Bypass Damper Actuator is
used to maintain the Duct Static Pressure Setpoint. The Static Pres-
sure Output Signal varies to control to the Static Pressure Setpoint.
The Duct Static Pressure is maintained at this setpoint anytime the
Main Fan is running.
The Duct Static Setpoint accuracy is controlled by this value. No
Main Fan VFD changes are made if the static is within this range
of this setpoint.
Description
Minimum
Default
Maximum
Static Pressure Spt
0.10
″
WG
1.50
″
WG
3.0
″
WG
Deadband
0.01
″
WG
0.10
″
WG
0.50
″
WG
