83
(
Outputs
FANS
P.E.1
) and a second power exhaust relay
(
Outputs
FANS
P.E.2
) which controls a single speed fan
which is equal in capacity to the VFD running at full speed.
Controlling high-capacity power exhaust differs from normal
power exhaust in the following ways:
• The integral term is not used. The percentile commanded
speed of the VFD is used instead.
• A “clamp percent” configuration is added (
BP.CL
) to cre-
ate a deadband that will assist the algorithm in controlling
the second power exhaust relay.
If building pressure (BP) rises above the building pressure set
point (
BP.SP
) and the supply fan is on, building pressure con-
trol is initiated. Thereafter if the supply fan relay goes off or if
the building pressure drops below the
BP.SP
minus the build-
ing pressure set point offset (
BP.SO
) for 5 continuous minutes,
building pressure control will be stopped. The 5-minute timer
will continue to reset while the VFD is commanded to a posi-
tion > 0%. If the building pressure falls below the set point, the
VFD will shut down automatically. Any time building pressure
control becomes active, the exhaust fan relay turns on which
energizes the exhaust fan VFD.
After the exhaust fan relay turns on, PID control ensues with-
out an “I” term:
Error = BP –
BP.SP
K = 1000 *
BP.TM
/ 60 (normalize the PID control for run
rate)
P = K *
BP.P
* (error)
D = K *
BP.D
* (error – error computed last time through
the PID)
VFD control signal (clamped between 0 and 100%) =
VFD Output last time t (P + D)
NOTE: The sum of P + D will be clamped on any timed calcula-
tion to an internally calculated value which guarantees the VFD is
not commanded more or less an amount than it can achieve before
the next time VFD capacity is again calculated. Bringing the sin-
gle speed fan (
P.E.2
) ON and OFF is coordinated with the VFD
speed. When building pressure first becomes active,
P.E.2
is OFF,
P.E.1
is ON and the VFD is allowed to climb to 100%.
BP.CL
will
be used to act as hysteresis so that when the P + D term is evaluat-
ed and it exceeds
BP.CL
, the control will go through a one-minute
period hold off time where the VFD is commanded to
BP.CL
, and
P.E.2
is brought on. After the transition to
P.E.2
ON is complete,
the control will continue to control the VFD from
BP.CL
%. If BP
rises, the control will speed up the VFD. Should the VFD drop to
0%, and the next time through the PID the P + D term calculation
is less than –
BP.CL
, the control will go through another one-min-
ute PID hold off period where
P.E.2
is commanded OFF and the
VFD is commanded to 100 –
BP.CL
.
Configuration
BP
BP.CF =5 (Return/Exhaust Control)
Fan tracking is the method of control used on plenum return fan
option. The fan tracking algorithm controls the exhaust/return
fan VFD and the exhaust fan relay. The
Comfort
Link controls
use a flow station to measure the flow of both the supply and the
return fans. The speed of the return fan is controlled by main-
taining a delta cfm (usually with supply airflow being greater of
the two) between the two fans. The building pressure is con-
trolled by maintaining this delta cfm between the two fans. In
general, the greater the delta between supply airflow and return
airflow, the higher the building pressure will be. Conversely, as
the return airflow quantity increases above the supply airflow,
the lower the building pressure will be. Whenever there is a re-
quest for the supply fan (or there is the presence of the IGC feed-
back on gas heat units), the return fan is started. The delta cfm is
defined as
S.CFM
–
R.CFM
. The return fan VFD is controlled
by a PID on the error of delta cfm actual from delta cfm set
point. If the error is positive, the drive will increase speed. If the
error is negative, the drive will decrease speed.
NOTE: These configurations are used only if Fan Tracking Learn-
ing is enabled. When Fan Tracking Learning is enabled, the con-
trol will adjust the delta cfm (
FT.ST
) between the supply and re-
turn fan if the building pressure deviates from the Building Pres-
sure Set Point (
BP.SP
). Periodically, at the rate set by the fan track
learn rate (
FT.TM
), the delta cfm is adjusted upward or downward
with a maximum adjustment at a given instance to be no greater
than fan track max correction (
FT.AD
). The delta cfm cannot ever
be adjusted greater than or less than the fan track initial delta cfm
(
FT.ST
) than by the Fan Track Max Clamp (
FT.MX
).
CONFIGURING THE BUILDING PRESSURE ACTUA-
TORS (
BP.CF
= 2) TO COMMUNICATE VIA ACTUATOR
SERIAL NUMBER
Every actuator used in the P Series control system has its own
unique serial number. The rooftop control uses this serial num-
ber to communicate with the actuator. These serial numbers are
programmed at the factory and should not need changing.
Should field replacement of an actuator become necessary, it
will be necessary to configure the serial numbers of the new
actuator. Four individual numbers make up each serial number
and these can be programmed to match the serial number of the
actuators in the building pressure actuator configurations
group,
ACT.C.
BP.1
and
BP.2
(
SN.1, SN.2, SN.3, SN.4
).
NOTE: The serial numbers can be found inside the control doors
of the unit as well as on the actuator itself. If an actuator is re-
placed in the field, it is a good idea to remove the additional peel-
off serial number sticker on the actuator and cover up the old one
inside the control doors.
CONTROL ANGLE ALARM CONFIGURATION (
C.ALM)
(
BP.CF
= 2)
The building pressure actuators learn what its end stops are
though a calibration at the factory. Field-installed actuators
may be calibrated in the Service Test mode. When an actuator
learns its end stops through calibration, it stores the control an-
gle. The actuator will resolve this control angle and express its
operation in a percent (%) of this learned range.
If a building pressure actuator has not learned a sufficient con-
trol angle during calibration, the actuator will be unable to con-
trol building pressure. For this reason, the building pressure ac-
tuators used in the P Series control system have configurable
control angle alarm low limits in the Building Pressure Actua-
tor Configurations group,
ACT.C
BP.1
and
BP.2.
(
C.A.LM
).
If the control angle learned through calibration is less than
C.A.LM
, an alert will occur and the actuator will not function.
NOTE: This configuration does not typically need adjustment. It
is configurable for the small number of jobs which may require a
custom solution or workaround.
Smoke Control Modes
There are four smoke control modes that can be used to control
smoke within areas serviced by the unit: Pressurization mode,
Evacuation mode, Smoke Purge mode, and Fire Shutdown. Evac-
uation, Pressurization and Smoke Purge modes require the con-
trols expansion module (CEM) board. The Fire Shutdown input is
located on the main base board (MBB) on terminals TB201-1 and
2. The unit may also be equipped with factory-installed return/
supply air smoke detector that is wired to TB201-1,2 and will shut
the unit down if a smoke condition is determined. Field-monitor-
ing wiring can be connected to terminal TB201-1 and 2 to monitor
the smoke detector. Inputs on the CEM board can be used to put
the unit in the Pressurization, Evacuation, and Smoke Purge
modes. These switches or inputs are connected to TB202: Pressur-
ization — TB202-18 and 19, Evacuation — TB202-16 and 17,
and Smoke Purge — TB202-14 and 15. Refer to Major System
Components section starting on page 129 for wiring diagrams.
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 ...