York YK-EP B Operation & Maintenance Manual page 162

SECTION 3 - DISPLAY MESSAGES
1. Leaving Chilled Liquid – Low temperature
2. Remote Stop
3. Multi-Unit Cycling – Contacts Open
4. System Cycling – Contacts Open
5. Control Panel – Schedule
6. Operator Initiated at Keypad
While the Vanes are closing during any Soft Shutdown,
if a Local Stop is initiated with the Compressor Switch
or any faults other than those listed above occur, the
Soft Shutdown is terminated and it will immediately
perform a System Coastdown.
RUN MESSAGES
Leaving Chilled Liquid Control
The chiller is running, controlling the Leaving Chilled
Liquid to the Leaving Chilled Liquid Temperature Set-
point. There are no system conditions inhibiting this
operation.
Heat Pump – Leaving Chilled Liquid Control
The Heat Pump is running, controlling the Leaving
Chilled Liquid Temperature to the Leaving Chilled
Liquid Temperature Setpoint. In this mode, Heat Pump
Duty is enabled and the Heat Pump Duty Operational
mode setpoint is set to Cooling mode.
Current Pulldown Limit
The Pulldown Demand Limit Setpoint timer is in effect
and the Compressor Motor current is greater than or
equal to the Pulldown Demand Current Limit Setpoint
value. The Pre-Rotation Vane operation is being inhib-
ited as described in Motor – High Current Limit mes-
sage below.
Motor – High Current Limit
The Compressor Motor current is greater than or equal
to the local or remote Current Limit Setpoint. The Cur-
rent Limit Setpoint is programmed over a range of 30
to 100% of the Chiller Full Load Amps (FLA). When
the motor current increases to the Inhibit Open thresh-
old, the Pre-Rotation Vanes are inhibited from further
opening. This prevents a further current rise. If the
current continues to rise to the Start Close threshold,
the Vanes begin closing until the current falls to the
Stop Close threshold. Automatic Vane operation is re-
sumed and this message automatically clears when the
motor current decreases to the Allow Open threshold.
162
The thresholds are different for the various motor start-
er applications. To allow field calibration of the Solid
State Starter (Mod "A") Logic Board or CM-2 Current
Module, pressing the Pre-Rotation Vanes OPEN key in
SERVICE access level, starts a 10 minute timer during
which the current limit thresholds are elevated. Refer to
table:
MOTOR CURRENT (%FLA)
ELECTRO-
VANE CONTROL
MECHANICAL/
SOLID STATE
STARTER
On rise, inhibit open
On fall, allow open
On rise, start close
On fall, stop close
An example of current limit is as follows: If a Solid
Sate Starter chiller FLA is 100 Amps, and the Current
Limit Setpoint is 50%, the following will occur:
50 Amps – inhibit vane open
52 Amps – vanes begin closing
51 Amps – vanes stop closing
49 Amps – allow automatic vane control
Load Control Mode
Access Level Required: SERVICE
The Compressor Motor Variable Speed Drive has not
yet reached full speed after having been commanded to
do so in Manual Speed Control mode. While this is dis-
played, the Pre-Rotation Vanes are inhibited from fur-
ther opening.
START INHIBIT MESSAGES
Anti-Recycle XX min/Sec
The chiller is inhibited from starting because the 30
minute anti-recycle time has not yet elapsed. Time re-
maining is displayed.
Vane Motor Switch Open
The chiller is inhibited from starting because the Pre-
Rotation Vanes are not fully closed.
Motor – Current >15% FLA
This start inhibit is instantaneously set whenever the
chiller is not running and a motor current of greater
than 15% FLA is detected. The oil pump is started as
FORM 160.87-OM1
ISSUE DATE: 8/24/2018
SERVICE
VSD
MODE
100 100 107
98 98 106
104 103 110
102 101 109
JOHNSON CONTROLS