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41
when the heat pump software is downloaded to the board. Oc-
cupancy types are described in the scheduling section below.
The following sections describe 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 spec-
ified occupied heating and cooling set points. The controller is
defaulted to control by occupied set points all the time, until ei-
ther a time schedule is configured with BACview
6
, Field Assis-
tant, i-Vu
®
Open, or a third party control system to enable/dis-
able the BAS (Building Automation System) on/off point. The
local time and date must be set for these functions to operate
properly. The occupancy 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 either Field
Assistant, i-Vu Open, BACview
6
or a third party control sys-
tem 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 assign a time
schedule to the controller.
Schedule_schedule
— The unit will operate according to the
schedule configured and stored in the unit. The schedule 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 Password (1111), then go to
schedule_schedule. From here, enter either a Weekly or Excep-
tion schedule for the unit.
Occupancy Input Contact
— The WSHP Open controller has
the capability to use an external dry contact closure to deter-
mine the occupancy status of the unit. The Occupancy Sched-
ules 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 Always
On. In Auto mode, the fan is in intermittent operation during
both occupied and unoccupied periods. Continuous fan mode
is intermittent during unoccupied periods and continuous dur-
ing occupied periods. Always On mode operates the fan con-
tinuously 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 op-
erate after heating or cooling is stopped. The fan will continue
to run as long as the compressors, heating stages, or the dehu-
midification relays are on. If the SPT failure alarm or conden-
sate overflow alarm is active; the fan will be shut down imme-
diately regardless of occupancy state or demand.
Fan Speed Control (During Heating)
— Whenever heat is re-
quired and active, the control continuously monitors the sup-
ply-air temperature to verify it does not rise above the config-
ured 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 oper-
ating 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 be-
low 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.
COOLING — The WSHP Open controller will operate one or
two stages of compression to maintain the desired cooling set
point. The compressor outputs are controlled by the PI (propor-
tional-integral) cooling loop and cooling stages capacity algo-
rithm. They will be used to calculate the desired number of
stages needed to satisfy the space by comparing the space tem-
perature (SPT) to the appropriate cooling set point. The water
side economizer, if applicable, will be used for first stage cool-
ing in addition to the compressor(s). The following conditions
must be true in order for the cooling algorithm to run:
• Cooling is set to Enable.
• Heating mode is not active and the compressor time
guard has expired.
• Condensate overflow input is normal.
• If occupied, the SPT is greater than the occupied cooling
set point.
• Space temperature reading is valid.
• If unoccupied, the SPT is greater than the unoccupied
cooling set point.
• If economizer cooling is available and active and the
economizer alone is insufficient to provide enough
cooling.
• OAT (if available) is greater than the cooling lockout
temperature.
If all the above conditions are met, the compressors will be
energized as required, otherwise they will be deenergized. If
cooling is active and should the SAT approach the minimum
SAT limit, the fan will be indexed to the next higher speed.
Should this be insufficient and if the SAT falls further (equal to
the minimum SAT limit), the fan will be indexed to the maxi-
mum speed. If the SAT continues to fall 5 F below the mini-
mum SAT limit, all cooling stages will be disabled.
During Cooling mode, the reversing valve output will be
held in the cooling position (either B or O type as configured)
even after the compressor is stopped. The valve will not switch
position until the Heating mode is required.
The configuration screens contain the minimum SAT
parameter as well as cooling lockout based on outdoor-air
temperature (OAT) Both can be adjusted to meet various
specifications.
There is a 5-minute off time for the compressor as well as a
5-minute time delay when staging up to allow the SAT to
achieve a stable temperature before energizing a second stage
of capacity. Likewise, a 45-second delay is used when staging
down.