84
Each mode must be energized individually on discrete inputs
and the corresponding alarm is initiated when a mode is acti-
vated. The fire system provides a normally closed dry contact
closure. Multiple smoke control inputs sensed by the control
will force the unit into a Fire Shutdown mode.
FIRE SMOKE INPUTS
These discrete inputs can be found on the local display under
Inputs
FIRE
.
Fire Shutdown Mode
This mode will cause an immediate and complete shutdown of
the unit.
Pressurization Mode
This mode attempts to raise the pressure of a space to prevent
smoke infiltration from an adjacent space. Opening the econo-
mizer (thereby closing the return air damper), shutting down
power exhaust, and turning the indoor fan on will increase
pressure in the space.
Evacuation Mode
This mode attempts to lower the pressure of the space to pre-
vent infiltrating an adjacent space with its smoke. Closing the
economizer (thereby opening the return-air damper), turning
on the power exhaust, and shutting down the indoor fan de-
crease pressure in the space.
Smoke Purge Mode
This mode attempts to draw out smoke from the space after the
emergency condition. Opening the economizer (thereby clos-
ing the return-air damper) and turning on both the power ex-
haust and indoor fan will evacuate smoke and bring in fresh air.
AIRFLOW CONTROL DURING THE FIRE/SMOKE MODES
All non-smoke related control outputs will get shut down in the
fire/smoke modes. Those related to airflow will be controlled
as explained below. The following matrix specifies all actions
the control will undertake when each mode occurs (outputs are
forced internally with CCN priority number 1 - “Fire”):
*
“FSO” refers to the supply and exhaust VFD fire speed override configurable
speed.
RELEVANT ITEMS:
The economizer’s commanded output can be found in
Out-
puts
ACTU
ECN.C
.
The configurable fire speed override for supply fan VFD is in
Configuration
SP
SP.FS
.
The supply fan relay’s commanded output can be found in
Out-
puts
FANS
S.FAN
.
The supply fan VFD’s commanded speed can be found in
Out-
puts
FANS
S.VFD
.
The configurable fire speed override for exhaust VFD/actuator
is in
Configuration
BP
B.V.A
BP.FS
.
The exhaust fan VFD’s commanded speed can be found in
Outputs
FANS
E.VFD
.
The power exhaust actuators command positions can be found
in
Outputs
ACTU
BPx.C
.
Indoor Air Quality Control
The indoor air quality (IAQ) function will admit fresh air into
the space whenever space air quality sensors detect high levels
of CO
2
. When a space or return air CO
2
sensor is connected to
the unit control, the unit’s IAQ routine allows a demand-based
control for ventilation air quantity, by providing a modulating
outside air damper position that is proportional to CO
2
level.
The ventilation damper position is varied between a minimum
ventilation level (based on internal sources of contaminants
and CO
2
levels other than from the effect of people) and the
maximum design ventilation level (determined at maximum
populated status in the building). Demand Controlled Ventila-
tion (DCV) is also available when the
Comfort
Link unit is con-
nected to a CCN system using ComfortID™ terminal controls.
This function also provides alternative control methods for
controlling the amount of ventilation air being admitted, in-
cluding fixed outdoor air ventilation rates (measured as cfm),
external discrete sensor switch input, and externally generated
proportional signal controls.
The IAQ function requires the installation of the factory-option
economizer system. The DCV sequences also require the con-
nection of accessory (or field-supplied) space or return air CO
2
sensors. Fixed cfm rate control requires the factory-installed out-
door air cfm option. External control of the ventilation position
requires supplemental devices, including a 4 to 20 mA signal, a
10,000 ohms potentiometer, or a discrete switch input, depend-
ing on the method selected. Outside air CO
2
levels may also be
monitored directly and high CO
2
economizer restriction applied
when an outdoor air CO
2
sensor is connected. (The outdoor CO
2
sensor connection requires installation of the CEM.)
The
Comfort
Link controls have the capability of DCV using an
IAQ sensor. The IAQ is measured using a CO
2
sensor whose
measurements are displayed in parts per million (ppm). The IAQ
sensor can be field-installed in the return duct. There is also an
accessory space IAQ sensor that can be installed directly in the
occupied space. The sensor must provide a 4 to 20 mA output
signal. The sensor connects to TB201 terminals 7 and 8. Be sure
to leave the 182-ohm resistor in place on terminals 7 and 8.
OPERATION
The unit’s indoor air quality algorithm modulates the position
of the economizer damper between two user configurations de-
pending upon the relationship between the
IAQ
and the outdoor
air quality (
OAQ
). Both of these values can be read at the
In-
puts
AIR.Q
submenu. The lower of these two configurable
positions is referred to as the IAQ Demand Vent Min Position
(
IAQ.M
), while the higher is referred to as Economizer Mini-
mum Position (
EC.MN
). The
IAQ.M
should be set to an econ-
omizer position that brings in enough fresh air to remove con-
taminants and CO
2
generated by sources other than people.
The
EC.MN
value should be set to an economizer position that
brings in enough fresh air to remove contaminants and CO
2
generated by all sources including people. The
EC.MN
value is
the design value for maximum occupancy.
The logic that is used to control the dampers in response to
IAQ conditions is shown in Fig. 13. The
Comfort
Link controls
will begin to open the damper from the
IAQ.M
position when
the IAQ level begins to exceed the OAQ level by a configu-
rable amount, which is referred to as Differential Air Quality
Low Limit (
DAQ.L
).
If OAQ is not being measured, OAQ can be manually config-
ured. It should be set at around 400 to 450 ppm or measured
with a handheld sensor during the commissioning of the unit.
The OAQ reference level can be set using the OAQ Reference
Set Point (
OAQ.U
). When the differential between IAQ and
OAQ reaches the configurable Diff. Air Quality Hi Limit
(
DAQ.H
), then the economizer position will be
EC.MN
.
When the IAQ–OAQ differential is between
DAQ.L
and
DAQ.H
, the control will modulate the damper between
IAQ.M
ITEM
EXPANSION
RANGE
CCN
POINT
WRITE
STATUS
FIRE
FIRE-SMOKE INPUTS
FSD
Fire Shutdown Input
ALRM/NORM
FSD
forcible
PRES
Pressurization Input
ALRM/NORM
PRES
forcible
EVAC
Evacuation Input
ALRM/NORM
EVAC
forcible
PURG
Smoke Purge Input
ALRM/NORM
PURG
forcible
DEVICE
PRESSURIZATION PURGE EVACUATION FIRE SD
Economizer
100%
100%
0%
0%
Indoor Fan — VFD/
ON/FSO*
ON/FSO*
OFF
OFF
Power Exhaust
VFD-Actuator
OFF
ON/FSO*
ON/FSO*
OFF
Heat Interlock Relay
ON
ON
OFF
OFF
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 ...