Carrier 50HCQ04---12 - Manual (Page 17)

17
USERPW
This submenu screen allows you to change the user
password to a four number password of choice. The User
password change screen is only accessible with the
Administrator Password (1111). The ADMIN password
will always override the user password.
Factory Default = 0000
Range = 0000--9999
OPERATION
The RTU-OPEN will control the compressors, economizer
and heating outputs based on its space temperature input
and setpoints. It can also be controlled by a building
control system or zoning system. An optional CO
2
IAQ
sensor mounted in the space can influence the economizer
minimum position. The RTU-OPEN has a hardware clock
that can allow scheduling for stand-alone operation. The
RTU-OPEN’s default is to control to occupied setpoints
all the time, until a type of occupancy control is set. The
following sections describe the operation for the functions
of the RTU-OPEN.
Occupancy
Occupancy is the fundamental overall control of
equipment. The unit can be in one of two states:
Occupied or Unoccupied. These are usually referred to as
periods because they represent periods of any given day.
Before RTU-OPEN can operate specific functions of the
equipment it is installed on, occupancy must be
determined. There are four different ways RTU-OPEN
can determine occupancy. These are described below and
selected by the configuration point Occupancy Source.
Always Occupied (Default)
The unit will not determine occupancy and continuously
run in the occupied state or period. RTU-OPEN ships from
the factory with this setting to allow immediate operation.
BACnet Schedule
When Occupancy Source is set to BACnet Schedule,
RTU-OPEN will use a schedule to change occupancy
based upon a day of week and a time period. Local time
and date should be set in the RTU-OPEN for this function
to operate properly. This function applies if setting a local
schedule in the RTU-OPEN or if applying the unit to an
I-Vu Open network or an OPEN zoning system. An
OPEN network schedule can override a local schedule
within the unit. A space sensor push button override is
only available when running a local or OPEN schedule.
The push button will override an unoccupied period to
occupied for the specified time duration.
BAS On/Off
When Occupancy Source is set to BAS On/Off,
RTU-OPEN follows occupancy based on an On/Off
command to the BAS ON/OFF software point. An on
command sets the occupancy to occupied, and an off
command sets it to unoccupied. The Building Automation
System can be speaking BACnet, Modbus, N2, or LON
and is writing to the BAS On/Off point in the open
protocol point map.
Remote Occ Input
When Occupancy Source is set to Remote Occ Input,
RTU-OPEN follows occupancy based on the remote
occupancy switch input. Inputs 3, 5, 8, and 9 on plug J5
can be hard-wired to command the unit’s occupancy. The
Occupancy Contact point show the status as on or off, on
is occupied and off is unoccupied.
Indoor (Supply) Fan
The indoor fan can be configured to operate in three
different manors. The configuration point Fan Mode
determines how the fan will run. The fan will always be
disabled if a fire shutdown or safety chain alarm is active.
A valid space temperature and supply air temperature
must be available for the fan to operate. There is a unit
start delay in effect when the unit is transitioning from
unoccupied to occupied. The following describes specific
fan operation based on the Fan Mode configuration value.
Auto
When Fan Mode is set to Auto, RTU-OPEN will cycle the
fan on and off based on the demand for heating, cooling,
and dehumidification. There is a configurable fan off
delay that is upheld before shutting the fan off after
conditioning has ended.
Continuous
When Fan Mode is set to Continuous, RTU-OPEN will
cycle the fan based on occupancy. The fan will run the
whole occupied period and operate in the auto mode
during the unoccupied period.
Always On
When Fan Mode is set to Always On, RTU-OPEN will run
the fan all the time regardless of occupancy or demand.
The RTU-OPEN has an optional Supply Fan Status input
to provide proof of airflow. If this is enabled, the point
will look for a contact change whenever the Supply Fan
Relay is on. If it is not enabled then it will always be the
same state as the Supply Fan Relay. The cooling,
economizer, heating, dehumidification, CO
2
and power
exhaust routines will use this input point for fan status.