York YK-EP B Operation & Maintenance Manual page 63

FORM 160.87-OM1
ISSUE DATE: 8/24/2018
VGD Control State
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
PROGRAMMABLE
Extreme Stall Duration
Access Level Required: SERVICE
(10 to 20 minutes; default 10 minutes.)
The Extreme Duration override occurs when the Vari-
able Geometry Diffuser (VGD) stall voltage is two
times higher than the high limit for longer than 10 min-
utes. At this time, the VGD will be opened and a warn-
ing 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.
PRV VGD Inhibit
Access Level Required: SERVICE
(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.
PRV Offset
Access Level Required: SERVICE
(0 to 5%, Default 3%)
When VGD control enters the Wait State, the PRV po-
sition 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.
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
Stall Wait Time
Access Level Required: SERVICE
(0.5 to 15 minutes, Default 10 minutes)
After the VGD control detects a stall and enters Stall
Wait State. It will wait for 10 minutes before going into
the probing (Open) mode.
Open Pulse
Access Level Required: SERVICE
(1 to 5 seconds, Default 2 seconds)
In the Probing State, VGD opens in pulse. The pulse
length is 10 seconds. The VGD will open for 2 sec-
onds and hold during the rest of the pulse period (8
seconds). This pulse repeats the 10 second pulse over
and over again until the stall voltage is higher than the
high limit.
High Limit
Access Level Required: SERVICE
(0.35 to 1.20V, Default 0.8V)
If stall voltage is higher than high limit of 0.8V, the
VGD control enters the stall react state that closes the
VGD. It will keep closing the VGD until stall volt is
lower than the low limit 0.5V.
Low Limit
Access Level Required: SERVICE
(0.30 to 0.79V, Default 0.50V)
When stall voltage is lower than low limit, the VGD
control enters the Wait state.
NAVIGATION
Home
Access Level Required: SERVICE
Returns user to HOME Screen.
Economizer VGD
Access Level Required: SERVICE
Pressing this button will return to the Economizer
VGD screen.
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