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NSKW INSTALLATION MANUAL
FX10 Advanced Control Overview
• The Johnson Controls FX10 board is specifically designed
for commercial heat pumps and provides control of the
entire unit as well as input ports for Open N2, LonTalk,
BACnet (MS/TP @ 19,200 Baud Rate) communication
protocols as well as an input port for a user interface.
The user interface can be used to aid in diagnostics and
unit setup and is optional on all NSKW units. A 16-pin low
voltage terminal board provides terminals for common
field connections. The FX10 Control provides:
• Operational sequencing
• High and low-pressure switch monitoring
• General lockout
• Freeze Detection Temperature Sensing
• Lockout mode control
• Emergency shutdown mode
• Random start and short cycle protection
Short Cycle Protection
Allows a minimum compressor “off” time of five minutes
and a minimum “on” time of two minutes.
Random Start
A delay of 1 to 120 seconds is generated after each power-
up to prevent simultaneous startup of all units within a
building after the release from an unoccupied cycle or
power loss.
Emergency Shutdown
A field-applied dry contact can be used to place the control
into emergency shutdown mode. During this mode, all
outputs on the board are disabled.
Freeze Detection Temperature Limit
Field selectable for -9.4° or -1.1°C
Installation Options
• Standalone controlled by standard aqua stat
• Integrated into BAS by adding communication module
Accessory Outputs
Quantity 2. Cycled with the compressor. Field selectable for
normally open (factory default) or normally closed through
the building automation system or user interface.
User Interface
4 x 20 backlit LCD
Optional Plug-in Communication Modules -
(compatible with standard BAS protocols)
• Open
N2
• LonTalk
• BACnet (MS/TP @ 19,200 Baud Rate, 30 unit max per
trunk line)
Display
One local display is optional on all NSKW units. Up to
2 displays, either 1 local and 1 remote, or 2 remote. (A
2-display configuration requires identical displays.) Local
display can be up to 3 meters from the controller, power
supply, and data communication. Remote display can be up
to 300 meters from the controller. Remote display must be
independently powered with data communication done via
3 pole shielded cable.
Control Timing & Fault Recognition Delays
Lead compressor “ON” delay ..........................................90 seconds
(not applicable for single compressor models)
Minimum compressor “ON” time ...................................... 2 minutes
(except for fault condition)
Short cycle delay ..................................................................... 5 minutes
Random start delay .......................................................0-120 seconds
High pressure fault ................................................................. <1 second
Low pressure fault ...............................................................30 seconds
Freeze detection fault ................................................... 0-30 seconds
Low pressure/freeze fault bypass..................................... 2 minutes
Optional Controls - FX10 cont.
Main FX 10 Board
