Economizer Compressor Screen; Figure 13 - Economizer Compressor Screen - York YK-EP B Operation & Maintenance Manual

FORM 160.87-OM1
ISSUE DATE: 8/24/2018

FIGURE 13 - ECONOMIZER COMPRESSOR SCREEN

OVERVIEW
This screen displays a cutaway view of the Econo-
mizer compressor, revealing the impeller, and shows
all conditions associated with the compressor. In ad-
dition, with the proper access level, the Pre-Rotation
Vanes may be manually controlled. Animation of the
compressor impeller indicates whether the chiller is
presently in a RUN condition. This screen also serves
as a gateway to subscreens for calibrating the Pre-
Rotation Vanes, calibrating the Proximity Probe, con-
figuring the Hot Gas Bypass, or providing advanced
control of the Compressor Motor Variable Speed
Drive.
DISPLAY ONLY
Oil Pressure
Displays the pressure differential between the high
side oil pressure transducer (compressor bearing input)
and the low side oil pressure transducer (oil sump). The
displayed value includes offset pressure derived from
auto-zeroing during the System Prelube. If either of the
transducers used to calculate this differential is out of
range, the display field will show XX.X.
JOHNSON CONTROLS

ECONOMIZER COMPRESSOR SCREEN

SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
The offset pressure is the pressure differential between
the high oil pressure (HOP) transducer and the low
oil pressure (LOP) transducer outputs during a three
(3) second period beginning ten (10) seconds into the
System Prelube. During this time, the transducers will
be sensing the same pressure and their outputs should
indicate the same pressure. However, due to accuracy
tolerances in transducer design, differences can ex-
ist. Therefore, to compensate for differences between
transducers and assure differential pressure sensing ac-
curacy, the offset pressure is subtracted algebraically
from the differential pressure. The offset pressure cal-
culation will not be performed if either transducer is
out of range. The offset value will be taken as 0 PSI in
this instance.
Oil Pump Drive Command Frequency
Displays the command frequency of the Oil Pump
Drive. The frequency will go up or down to match the
pump motor output to the required oil pressure.
Discharge Temperature
Displays the temperature of the refrigerant in its gas-
eous state at discharge of the compressor as it travels
to the condenser.
LD19628
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