Quantech QWC4, Installation Operation & Maintenance, Page: 90 / 156

QUANTECH
90
FORM QWC4-NM1 (221)
ISSUE DATE: 02/28/2021
SECTION 6 - OPERATION
rator pressure and overcome low differential pressure
to maintain oil flow.
Load or Unloading Limit Messages
The following messages show that the designated load
limit or unloading is in effect.
DISCHARGE PRESSURE LIMITING
EVAPORATOR PRESSURE LIMITING
MOTOR CURRENT LIMITING
PULLDOWN MOTOR CURRENT LIMITING
CURRENT LIMITING
The motor current load limit or unloading is in ef-
fect through the use of the BAS setpoint offset. The
BAS current limit must be activated for this function
to operate.
REMOTE MOTOR CURRENT LIMITING
The motor current load limit or unloading is in effect
through the use of the remote setpoint offset, which
may be offset using a remote voltage or a current sig-
nal. The remote current limit must be activated for this
function to operate.
VSD BASEPLATE TEMP LIMITING
The VSD baseplate temperature is high, resulting in
load limiting or unloading.
VSD INTERNAL AMBIENT TEMP LIMITING
The VSD internal ambient temperature is high, result-
ing in load limiting or unloading.
CHILLED LIQ LEAVE TEMP LIMITING
Applicable in HEAT PUMP mode only.
UNIT STATUS
CONDENSER LIQUID FLOW SWITCH SHUTDOWN
The flow switch is open, which is preventing the unit
from running. There is a one second delay until the unit
shuts down.
UNIT STATUS
VSD COOLING SHUTDOWN
The chiller is shutdown, but is running the auxiliary
coolant pump, to bring the VSD ambient temperature
down to an acceptable level before allowing the unit
to start.
REMOTE RUN CONTACT IS OPEN
The system remote run permissive input is open, pre-
venting that system from running. There is a one sec-
ond delay until the unit shuts down.
SYSTEM SWITCH IS OFF
The system is prevented from running by selecting
OFF with the SYSTEM SWITCHES key.
COOLING DEMAND SHUTDOWN
This message is only displayed in NORMAL SHUT-
DOWN HISTORY to indicate a capacity controlled
shutdown based on cooling and heating demand.
COMPRESSOR RUNNING
The system is running due to demand.
SHUTTING DOWN
The system is ramping down to shut down. This mes-
sage is displayed after the software run signal is disabled
until the VSD notifies the control board that the com-
pressor is no longer running.
ANTI-RECYCLE TIMER = ### SEC
The amount of time remaining on the anti-recycle tim-
er is shown, and the system is unable to start due to the
timer being active.
OPD MITIGATION
OPD is Oil Pressure Differential. Condenser level con-
trol is repositioning the level setpoint to reduce evapo-