75
Fan Enable (Analog IAQ Sensor)
The DCV algorithm will operate whenever the building is
occupied and the indoor fan is operating or whenever the IAQ
algorithm has caused the indoor fan to operate. The configuration
Configuration
→
AIR.Q
→
IA.FN
(Fan Enable for IAQ),
determines whether or not the IAQ algorithm can turn on the
indoor fan. If the indoor fan is not operating, the economizer
position will be zero. The damper position may exceed
Configuration
→
AIR.Q
→
EC.MN
to
provide
economizer
cooling.
Configuration
→
AIR.Q
→
IA.FN = 0 (Never)
When
IA.FN = 0
, the IAQ algorithm can never turn on the fan.
Configuration
→
AIR.Q
→
IA.FN = 1 (Occupied)
When
IA.FN
= 1
, the IAQ algorithm will turn on the indoor fan
whenever the building is occupied and IAQ/OAQ differential is
greater than the configuration
Configuration
→
AIR.Q
→
DF.ON
(Fan On AQ Differential). The indoor fan will turn off when the
IAQ/OAQ
differential
is
less
than
the
configuration
Configuration
→
AIR.Q
→
DF.OF
(Fan Off AQ Differential).
Configuration
→
AIR.Q
→
IA.FN = 2 (Always)
The indoor fan performance for
IA.FN
= 2
is the same as the
performance when
IA.FN
= 1
except the algorithm is not limited
to occupied periods only. The fan can be triggered on when the
space is occupied or unoccupied.
Fan Enable (Analog Switch Input)
The DCV algorithm will operate whenever the building is
occupied and the indoor fan is operating or the whenever the IAQ
algorithm has caused the indoor fan to operate. The configuration
Configuration
→
AIR.Q
→
II.FN
(IAQ Switch Input Fan CFG)
determines whether or not the IAQ algorithm can turn on the
indoor fan. If the indoor fan is not operating, the economizer
position will be zero. The damper position may exceed
Configuration
→
AIR.Q
→
EC.MN
to
provide
economizer
cooling.
Configuration
→
AIR.Q
→
II.FN = 0 (Never)
When
II.FN
= 0
, the IAQ algorithm can never turn on the fan.
Configuration
→
AIR.Q
→
II.FN = 1 (Occupied)
When
II.FN
= 1
, the IAQ algorithm will turn on the indoor fan
whenever the building is occupied and IAQ is high. The indoor
fan will turn off if IAQ returns to normal.
Configuration
→
AIR.Q
→
II.FN = 2 (Always)
The indoor fan performance for
II.FN
= 2
is the same as the
performance when
II.FN
= 1
except the algorithm is not limited
to occupied periods only. The fan can be triggered on when the
space is occupied or unoccupied.
Temperature Compensated Start
This logic is used when the unit is in the unoccupied state. The
control will calculate early Start Bias time based on Space
Temperature deviation from the occupied cooling and heating set
points. This will allow the control to start the unit so that the
space is at conditioned levels when the occupied period starts.
This is required for ASHRAE 90.1 compliance. A space sensor is
required for non-linkage applications.
Setting Up the System
The settings for temperature compensated start can be found in
the local display under
Configuration
→
UNIT
.
ITEM
EXPANSION
RANGE UNITS CCN POINT
TCS.C
Temp.Cmp.Strt.Cool Factr
0 - 60
min
TCSTCOOL
TCS.H
Temp.Cmp.Strt.Heat Factr
0 - 60
min
TCSTHEAT
Temp Comp Strt Cool Factr (TCS.C)
This is the factor for the start time bias equation for cooling.
Temp Comp Strt Heat Factr (TCS.H)
This is the factor for the start time bias equation for heating.
NOTE
: Temperature compensated start is disabled when these
factors are set to 0.
Temperature Compensated Start Logic
The following conditions must be met for the algorithm to run:
S
Unit is in unoccupied state.
S
Next occupied time is valid.
S
Current time of day is valid.
S
Valid space temperature reading is available (sensor or
CCN network).
The algorithm will calculate a Start Bias time in minutes using the
following equations:
If (space temperature > occupied cooling set point)
Start Bias Time = (space temperature – occupied cooling set
point)*
TCS.C
If (space temperature < occupied heating set point)
Start Bias Time = (occupied heating set point – space
temperature)*
TCS.H
When the Start Bias Time is greater than zero the algorithm will
subtract it from the next occupied time to calculate the new start
time. When the new start time is reached, the Temperature
Compensated Start mode is set, the fan is started and the unit
controlled as in an occupied state. Once set, Temperature
Compensated mode will stay on until the unit goes into the
Occupied mode. The Start Bias Time will be written into the
CCN Linkage Equipment Table if the unit is controlled in DAV
mode. If the Unoccupied Economizer Free Cool mode is active
when temperature compensated start begins, the Unoccupied Free
Cool mode will be stopped.
Carrier Comfort Network (CCN)
R
Configuration
It is possible to configure the
Comfort
Link
™
control to
participate as an element of the Carrier Comfort Network (CCN)
system directly from the local display. This section will deal with
explaining the various programmable options which are found
under the CCN sub-menu in the Configuration mode.
The major configurations for CCN programming are located in
the local displays at
Configuration
→
CCN
.
See Appendix A.
CCN Address (CCN.A)
This configuration is the CCN address the rooftop is assigned.
CCN Address (CCN.B)
This configuration is the CCN bus the rooftop is assigned.
CCN Baud Rate (BAUD)
This configuration is the CCN baud rate.
CCN Time/Date Broadcast (BROD
→
B.TIM)
If this configuration is set to ON, the control will periodically
send the time and date out onto the CCN bus once a minute. If
this device is on a CCN network then it will be important to make
sure that only one device on the bus has this configuration set to
ON. If more than one time broadcaster is present, problems with
the time will occur.
NOTE
:
Only the time and date broadcaster can perform
daylight savings time adjustments. Even if the rooftop is stand
alone, the user may want to set this to ON to accomplish the
daylight/savings function.
CCN OAT Broadcast (BROD
→
B.OAT)
If this configuration is set to ON, the control will periodically
broadcast its outside-air temperature at a rate of once every 30
minutes.
48/
50P
G
C
03
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