York YK Style H Operation Manual page 171

FORM 160.76-O2
issue date: 6/15/2015
Oil – Low Temperature Differential
The chiller is prevented from starting because for one of
the following reasons. The chiller will automatically re-
start when the conditions have been satisfied. This condi-
tion is only checked while the chiller is stopped. In pre-
vious software versions, it is checked when stopped and
during the first 10 seconds of prelube.
The chiller has been shut down for less than or equal
to 30 minutes and the oil temperature minus the con-
denser saturation temperature is less than 30°F.
-OR-
The chiller has been shut down for greater than 30 min-
utes and the oil temperature minus the condenser satu-
ration temperature is less than 40°F.
-OR-
Following a power failure, upon restoration of power,
the oil temperature minus the condenser saturation
temperature is less than 40°F.
Oil – Low Temperature
The oil temperature has decreased to less than 55°F.
The chiller will automatically restart when the tem-
perature increases to greater than 55.0°F and is greater
than the Condenser Saturated temperature by 30 or
40°F, as described above in the Oil – Low Temperature
Differential message description.
Control Panel – Power Failure
A Control Power failure has occurred. If the power fail-
ure occurred while the chiller was running, it will auto-
matically restart when power is restored. However, if the
power failure duration was less than the duration of the
applicable coastdown period (2.5 minutes standard; 15
minutes steam turbine) when power is restored, the re-
mainder of the coastdown will be performed, prior to the
chiller starting. This message can indicate a Cycling (au-
to-restart after power failure) or Safety (manual restart
after power failure) shutdown, depending upon Control
Center configuration. It indicates a cycling shutdown
when displayed in orange characters; safety shutdown
when displayed in red characters. The Control Center is
configured for auto-restart or manual restart after power
failure by a qualified Service Technician following in-
structions in OptiView Control Center - Service Instruc-
tions (Form 160.76-M1).
JOHNSON CONTROLS
SECTION 3 - DISPLAY MESSAGES
Leaving Chilled Liquid – Low Temperature
The Leaving Chilled Liquid Temperature has decreased
to the programmed Shutdown Temperature Setpoint. If
the chiller is running when this occurs, the Pre-rotation
Vanes are driven fully closed prior to shutting down
the chiller. The chiller will automatically restart when
the temperature increases to the programmed Restart
Temperature Setpoint.
If the chiller is operating in Heat Pump Heating mode,
(Heat Pump Duty is enabled, and the Heat Pump Op-
erational mode setpoint is set to Heating), there is ad-
ditional logic that will cause this Shutdown when the
Leaving Chilled Liquid Temperature (LCHLT) de-
creases below the programmed Heating LCHLT Shut-
down Temperature Setpoint. For details of this setpoint,
refer to the HEAT PUMP Screen.
Leaving Condenser Liquid – High Temperature
The Leaving Condenser Liquid Temperature has in-
creased to the programmed Leaving Condenser Liquid
Temperature Cycling Offset - Shutdown Setpoint. This
shutdown is only applicable to Heat Pump Duty en-
abled and operating in Heating mode (Heat Pump Op-
erational Setpoint set to Heating mode). Refer to HEAT
PUMP Screen. Anytime the Leaving Condenser Liq-
uid Temperature Setpoint is decreased, the shutdown
threshold becomes 125°F for the next 10 minutes. Af-
ter 10 minutes have elapsed, the shutdown threshold
becomes the programmed setpoint value. The Heat
Pump will automatically restart when the temperature
decreases to the programmed Leaving Condenser Liq-
uid Temperature Cycling offset – Restart Setpoint.
Leaving Chilled Liquid – Flow Switch Open
The Chilled Liquid Flow Switch has remained open for
5 continuous seconds while the chiller was running or
failed to close during the System Prelube period. The
chiller will automatically restart when the flow switch
closes.
While this cycling shutdown is active, the evaporator
pump relay contacts (TB2-44/45) remain closed un-
til the chiller is given a stop command or has another
fault. With all previous software versions, these con-
tacts open at completion of coastdown.
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