York YK-EP Operation And Maintenance Manual page 72

Table 59: Display only
Field/LED name
Stall Count
Stall Time
VGD Control State
Table 60: Programmable
Button Access level
Extreme Stall
Service
Duration
PRV VGD
Service
Inhibit
PRV Offset Service
72
Description
Displays the number of times that the system had detected an
Economizer Compressor Stall.
Displays the accumulated time that the Stall Detector Board output
is greater than the High Limit Setpoint voltage while the chiller is
running.
Shows the current state of the VGD Control. It will show various
messages as follows:
• Undefined
• Disabled
• Stall Waiting
• Probing
• Stall Reacting
• PRV Override
• Sensor Failure Override
• Extreme Stall Override
• Manual Hold
• Manual Open
• Manual Close
• Inactive
Description
(10 to 20 minutes; default 10 minutes.)
The Extreme Duration override occurs when the Variable Geometry
Diffuser (VGD) stall voltage is two times higher than the high limit
for longer than 10 minutes. At this time, the VGD will be opened and
a warning message displayed. The VGD will remain open until the
warning is manually cleared by the operator. Once cleared, the VGD
Control will return to normal operation.
(40 to 100%, Default 95%)
If PRV position is greater than the PRV VGD Inhibit (95%), the VGD
will open in pulse mode just the same way as in the Probing state.
(0 to 5%, Default 3%)
When VGD control enters the Wait State, the PRV position is PRV
wait Start position. During the Wait state, if PRV position is greater
than the PRV wait Start + 3%, the VGD control will enter the Probing
state.
YK-EP Style B Centrifugal Chiller