Specifications

58
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
OPERATION
VSD CT Plug (Hardware) Fault
Jumpers are installed in each CT plug on the VSD Logic
Board to feed back signals to indicate if the plugs are
installed or not. If either plug is not installed, a low value
is read on the digital input and the unit will immediate
shutdown on a fault or will not run if off.
This is an auto-restart safety that will restart after the 120
second anti-recylce timer times out and lock out on the
3rd fault in 90 minutes. The fault is a unit fault for all
units. Following is the fault message.
UNIT FAULT:
VSD CT PLUG FAULT
FAULT indicates the system is in a "FAULT" condition
and will restart or "LOCKOUT" and will not restart until
the operator clears the fault using the keypad.
SYSTEM SAFETIES (FAULTS)
System Safety (Fault) Operation
System safeties are faults that cause individual systems
to be shut down if a safety threshold is exceeded for 3
seconds. System faults are auto reset faults in that the
system will be allowed to restart automatically after
the 120 second anti-recycle timer times out. The only
exception is after any 3 faults on the same system occur
within 90 minutes, that system will be “locked out” on
the last fault. The lockout condition requires a manual
reset using the system switch. The respective system
switch must be cycled OFF and ON to clear the lockout
fault.
When multiple systems are operating and a system
fault occurs, the running systems will ramp down and
the faulted system will be shut OFF and the previously
operating will restart if required after the fault clears and/
or the 120 second anti-recycle timer times out.
In the descriptions of the fault displays that follow, the
fault message will show a FAULT to indicate that a
system is in a “FAULT” condition and will restart when
the fault clears, or “LOCKOUT” and will not restart until
the operator clears the fault using the keypad. If a system
safety is in effect, the message will be displayed to the
operator when the STATUS key is pressed.
In some cases, a control panel fault will occur after a
VSD fault, possibly during system shutdown or at some
later time. This is known as an “ALL FAULT” and these
faults will be recorded as such under the HISTORY
information stored at the instant of the primary fault.
In some cases, this information may be valuable in
troubleshooting the primary fault. An example of the
“ALL FAULT” history message is shown on Page 215
under the HISTORY key. When an “ALL FAULT”
occurs, associated history information will not be stored.
If an additional fault does not occur, the “ALL FAULTS”
display will indicate NONE.
In cases where a VSD fault occurs during the rampdown
of a control panel fault (i.e.: low suction pressure, low
water temp, etc.), the VSD fault will be stored as a new
fault with the associated fault information stored at the
instant the VSD fault occurred (i.e.: IGBT Gate Drive,
Single Phase Input, VSD CT Plug, etc.). The control
panel fault that occurred prior to the VSD fault will be
stored with the associated complete data related to the
fault as a numerically lower numbered history in the
history buffers.
High Discharge Pressure Cutout (Software)
Fault
The High Discharge Pressure Cutout is a software fault.
A system will fault and shut down with a controlled
ramped shutdown on high discharge pressure when the
discharge pressure rises above 22.4 barg (325 PSIG) for
0.5 seconds. The system will be allowed to restart when
the discharge pressure falls to 20.3 barg (295 PSIG). The
system will also be inhibited from starting if the pressure
is above 20.3 barg (295 PSIG). The fault message for
this safety is shown below:
SYS X FAULT: HIGH DISCHARGE PRESSURE
The X indicates the system and FAULT indicates the
system is in a “FAULT” condition and will restart
when the 120 second anti-recycle timer times out, or
“LOCKOUT” and will not restart until the operator
clears the fault using the keypad.