Product data

52
WSHP Open sequence of operation
The WSHP Open multi-protocol controller will control me-
chanical cooling, heating and waterside economizer out-
puts based on its own space temperature input and set
points. An optional CO
2
IAQ (indoor air quality) sensor
mounted in the space can maximize the occupant comfort.
The WSHP Open controller has its own hardware clock
that is automatically set when the heat pump software is
downloaded to the board. Occupancy types are described
in the scheduling section below. The following sections de-
scribe the functionality of the WSHP Open multi-protocol
controller. All point objects referred to in this sequence of
operation will be referenced to the objects as viewed in the
BACview
6
handheld user interface.
Scheduling — Scheduling is used to start/stop the unit
based on a time period to control the space temperature to
specified occupied heating and cooling set points. The
controller is defaulted to control by occupied set points all
the time, until either a time schedule is configured with
BACview
6
, Field Assistant, i-Vu
®
Open, or a third party
control system to enable/disable the BAS (Building Auto-
mation System) on/off point. The local time and date must
be set for these functions to operate properly. The occu-
pancy source can be changed to one of the following:
Occupancy schedules
— The controller will be occupied
24/7 until a time schedule has been configured using ei-
ther Field Assistant, i-Vu Open, BACview
6
or a third party
control system to enable/disable the BAS on/off point.
The BAS point can be disabled by going to Config, then
Unit, then Occupancy Schedules and changing the point
from enable to disable then clicking OK.
NOTE: This point must be enabled in order for the i-Vu
Open, Field Assistant, or BACview
6
control system to as-
sign a time schedule to the controller.
Schedule_schedule
— The unit will operate according to
the schedule configured and stored in the unit. The sched-
ule is accessible via the BACview
6
Handheld tool, i-Vu
Open, or Field Assistant control system. The daily schedule
consists of a start/stop time (standard or 24-hour mode)
and seven days of the week, starting with Monday and
ending on Sunday. To enter a daily schedule, navigate to
Config, then Sched, then enter BACview
6
Admin Pass-
word (1111), then go to schedule_schedule. From here,
enter either a Weekly or Exception schedule for the unit.
Occupancy input contact
— The WSHP Open controller
has the capability to use an external dry contact closure to
determine the occupancy status of the unit. The Occupan-
cy Schedules will need to be disabled in order to utilize the
occupancy contact input.
NOTE: Scheduling can only be controlled from one
source.
BAS (Building Automation System) on/off
— A BAS
system that supports network scheduling can control the
unit through a network communication and the BAS
scheduling function once the Occupancy Schedules have
been disabled.
NOTE: Scheduling can either be controlled via the unit or
the BAS, but not both.
Indoor fan — The indoor fan will operate in any one of
three modes depending on the user configuration selected.
Fan mode can be selected as Auto, Continuous, or Al-
ways On. In Auto mode, the fan is in intermittent opera-
tion during both occupied and unoccupied periods. Contin-
uous fan mode is intermittent during unoccupied periods
and continuous during occupied periods. Always On mode
operates the fan continuously during both occupied and
unoccupied periods. In the default mode, Continuous, the
fan will be turned on whenever any one of the following is
true:
• The unit is in occupied mode as determined by its occu-
pancy status.
• There is a demand for cooling or heating in the unoccu-
pied mode.
• There is a call for dehumidification (optional).
When power is reapplied after a power outage, there
will be a configured time delay of 5 to 600 seconds before
starting the fan. There are also configured fan delays for
Fan On and Fan Off. The Fan On delay defines the delay
time (0 to 30 seconds; default 10) before the fan begins to
operate after heating or cooling is started while the Fan Off
delay defines the delay time (0 to 180 seconds; default 45)
the fan will continue to operate after heating or cooling is
stopped. The fan will continue to run as long as the com-
pressors, heating stages, or the dehumidification relays are
on. If the SPT failure alarm or condensate overflow alarm
is active; the fan will be shut down immediately regardless
of occupancy state or demand.
Automatic fan speed control
— The WSHP Open control-
ler is capable of controlling up to three fan speeds using
the ECM (electronically commutated motor). The motor
will operate at the lowest speed possible to provide quiet
and efficient fan operation with the best latent capability.
The motor will increase speed if additional cooling or heat-
ing is required to obtain the desired space temperature set
point. The control increases the motor's speed as the space
temperature rises above the cooling or below the heating
set point. The amount of space temperature increase
above or below the set point required to increase the fan
speed is user configurable in the set point. Also, the control
will increase the fan speed as the supply-air temperature
approaches the configured minimum or maximum limits.
Fan speed control (during heating)
— Whenever heat is re-
quired and active, the control continuously monitors the
supply-air temperature to verify it does not rise above the
configured maximum heating SAT limit (110 F default). As
the SAT approaches this value, the control will increase the
fan speed as required to ensure the SAT will remain within
the limit. This feature provides the most quiet and efficient
operation by operating the fan at the lowest speed
possible.
Fan speed control (during cooling)
— Whenever mechani-
cal cooling is required and active, the control continuously
monitors the supply-air temperature to verify it does not
fall below the configured minimum cooling SAT limit (50 F
default). As the SAT approaches this value, the control will
increase the fan speed as required to ensure the SAT will
remain within the limit. The fan will operate at lowest
speed to maximize latent capacity during cooling.
Controls