30
FAN OUTPUT — During occupied periods, the fan operation
is determined by the Occupied Fan Operation configuration de-
cision. If this decision is set to continuous (1), the fan will oper-
ate continuously during the occupied periods and during heat-
ing, cooling, and dehumidification during unoccupied periods.
If it is set to automatic (0), the fan will only operate only if
heating, cooling or dehumidification is required (and heating or
cooling is available in a 2-pipe changeover system). The Fan
Output point displays the status of the fan.
During unoccupied periods, the fan will only operate if at
least one of the following conditions is true:
• the Space Temperature exceeds the Cooling Set Point
and Cooling is available
• Space Temperature falls below the Heating Set Point and
Heating is available
• Space Humidity exceeds the Unoccupied High Humidity
limit and the Space Temperature is above the Heating set
point
• Space Humidity exceeds the Unoccupied High Humidity
limit, the Space Temperature is below the Heating set
point, the Heat Type is not None, and the unit is not con-
figured for 2-pipe Changeover (0)
• the control is configured for Unoccupied Fan Cycling
and the current minute is equal to the calculated
1-minute time interval.
The fan stops at the end of the occupied time if the above
conditions are satisfied. A 5-minute fan off delay will continue
to provide fan operation after a cooling cycle is completed and
under conditions where the fan would otherwise stop. This
function improves IAQ by evaporating residual coil moisture
(condensate) which contributes to bacteria growth.
The fan coil controller Unoccupied Fan Cycling option,
when enabled, causes the fan to run for one minute each hour
during unoccupied times. The exact time of operation is deter-
mined by the CCN address. The purpose of this mode is to pre-
vent air stagnation from causing the unit to operate or not oper-
ate based upon improperly sensing the space temperature
conditions.
Whenever a fan speed change is required, the zone control-
ler will disable the fan output (for approximately 1 second) pri-
or to changing the fan speed relays (FANSPD 1 and FANSPD
2). This will allow the speed relays to be switched under a no-
load condition and will also prevent excessive EMI from being
generated if the speed is being reduced. Once the fan speed re-
lays are correctly positioned, the fan relay will be re-energized.
Following the execution of the initialization routine, the Fan
Coil will delay an amount of time (in seconds) equal to the re-
mainder of the Level II address divided by 60, before turning
the fan on. This will allow for sequenced start-ups when more
than one Fan Coil is connected to the network.
Fan Output:
Display Units
Discrete ASCII
Default Value
Off
Display Range
Off/On
Network Access Read/Write
Alarm Service Configuration Table —
The Alarm
Service Configuration Table is used to configure the alarms
used on the fan coil controller. See Fig. 34.
ALARM ROUTING CONTROL — The Alarm Routing
Control decision indicates which CCN system software or de-
vices will receive and process alarms sent by the Fan Coil con-
troller. This decision consists of eight digits which can be set to
zero or one. A setting of one indicates alarms should be sent to
this device. A setting of zero disables alarm processing for that
device. Currently the corresponding digits are configured for
the following devices: first digit - user interface software
(ComfortWORKS
®
, ComfortVIEW™, etc.); second digit -
Autodial Gateway or Telink; fourth digit - Alarm Printer Inter-
face Module, DataLINK module; digits 3 and 5 through 8 - un-
used.
Alarm Routing
Control:
Range
00000000 to 1111111
Default Value
11010000
RE-ALARM TIME — This decision is used to configure the
number of minutes the fan coil controller will wait before an
alarm condition (which still exists) will be transmitted on the
communications network again. Re-alarming of an alarm con-
dition will continue until the condition no longer exists.
Re-Alarm Time: Units
Minutes
Range
0 to 1440
Default Value
0 (Disabled)
CONTROL TEMPERATURE HYSTERESIS — This con-
figuration defines the range above the high set point and below
the low set point the space temperature must exceed for an
alarm condition to exist during occupied hours.
Control Temperature
Hysteresis:
Units
delta F (delta C)
Range
1.0 to 20.0
Default Value
5
SUPPLY AIR TEMPERATURE — The Supply Air Temper-
ature High and Low Limit alarms are used to monitor the sup-
ply air temperature. If the temperature becomes too low or too
high, an alarm condition will exist.
Supply Air Temperature
Low Limit:
Units
degrees F (degrees C)
Range
–40.0 to 245.0
Default Value
45.0
Supply Air Temperature
High Limit:
Units
degrees F (degrees C)
Range
–40.0 to 245.0
Default Value
150
OCCUPIED RELATIVE HUMIDITY — The Occupied Rel-
ative Humidity alarm defines the allowable humidity levels
during occupied periods. If the humidity becomes too low or
too high, an alarm condition will exist.
Occupied Relative Humidity
Low Limit:
Units
% RH
Range
0 to 100
Default Value
30
Occupied Relative Humidity
High Limit
Units
% RH
Range
0 to 100
Default Value
70
UNOCCUPIED RELATIVE HUMIDITY — The Unoccu-
pied Relative Humidity alarm defines the allowable humidity
levels during unoccupied periods. If the humidity becomes too
low or too high, an alarm condition will exist.
Unoccupied
Relative Humidity
Low Limit:
Units
% RH
Range
0 to 100
Default Value
10
Unoccupied
Relative Humidity
High Limit:
Units
% RH
Range
0 to 100
Default Value
90
