Trane ZN. LonWorks control, Руководство пользователя

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CNT-SVX13B-E4 9
Features
Freeze avoidance function
This function has been especially
designed for units equipped with a
fresh air inlet. If the discharge air
temperature falls below the 'freeze
avoidance setpoint', then the
controller reacts in order to prevent
the coil to freeze. The fan is stopped,
the cooling and heating outputs are
energized.
Freeze protection
If the discharge air temperature
drops below the 'discharge air low
limit' then the unit shuts down and
must be restarted manually. See
'Resetting diagnostics'
Manual Output Test Function
This feature is an invaluable tool for
troubleshooting a unit. By simply
pressing the controller's test button,
service personnel can manually
exercise outputs in a pre-defined
sequence.
Binary inputs
Occupancy / windows contact
(B13 - J2-5/J2-6 on the controller)
To allow energy savings to take
place, the occupancy binary input
can be wired up to a motion sensor,
card reader, window contact or time
clock, and will turn the unit from
occupied to unoccupied mode
whenever the space occupancy is
not proved. This binary input is
factory-configured as Normally Open
(NO) and is used for two occupancy-
related functions:
• For stand alone controllers (any
unit not receiving a communicated
occupancy request)
• For controllers that receive a
communicated occupancy request
(typically from a building
automation system such as Tracer
Summit™):
Refer to Table 1 to see the effect of
the binary input upon the occupancy
state of the control.
Control features
Entering Water Temperature
Sampling Function (optional)
A 2-pipe changeover system that
uses a two-way control valve might
not sense the correct entering water
temperature during long periods
when the control valve is closed. This
function periodically samples the
entering water temperature by
opening the valve. Then the
controller reads the entering water
temperature for up to 3 minutes to
check if the correct water
temperature is available for the
selected operating mode. The
entering water temperature must be
2.5°K or more above the space
temperature to allow heating and
2.5°K or more below the space
temperature to allow cooling. If the
water temperature is not suitable
with the selected operating mode,
then a new sampling occurs 60
minutes later.
Note: This changeover sensor is
factory-wired and is coiled to the unit
side for mounting on customer-
supplied piping. This sensor must
detect accurate water temperature
for proper changeover.
Random Start
In order to reduce electrical spikes at
power up in the building, especially
when the units are equipped with
electric heater option, multiple unit
start-ups are randomly and
automatically staggered from 5 to
32 seconds.
Filter Maintenance Status
For ease of maintenance, the ZN
controller has a built-in timer that,
when it reaches zero, can initiate an
alarm notification to Trane Tracer
Summit™ system. The filter
maintenance status is based on
cumulative fan run hours. Factory
default value is 300 hours.
Water Valve Override
Using Tracer Summit™, the water
valve override function drives all
water valves in every unit fully open
simultaneously. This helps reduce
the time required for waterside
balancing. After two hours, if no
information has been sent, the
controller returns to its normal
operation.