TABLE 1 Continued. CONTROL COMPONENT SUMMARY
-
STANDARD APPLICATIONS
CONTROL
SYMBOL SETTING
RESET
LOCATION
SIGNAL
(Note 1)
LIGHT
FUNCTION
Oil Pump Time
Delav Switch
OTD
60 sec.
None
Relay
Section
None
Keeps pump
running
for 60 seconds after compressor is stopped.
Pushbutton Switch
PB None
None Switch
Section
None
Pushbutton switches reset the safety circuit when the RESET button
on the control panel is pushed.
Prelube Timer
Protective Signal
Interlock
PLT
PS
60 sec.
None
None
None
Relay
Section
Starter
None
Provides a pre-lubrication period for bearings prior to compressor
start.
Ext. Fail De-energizes system monitor timer when compressor starter closes
delta contactor
Phase Voltage Relay
PVR
None
Auto/Man Starter Ext. Fail Protects compressor against damage from single phase, phase rever-
sal or undervoltage.
Range Shift
Resistor
RSR None
None Control
Module
None
Provides temperature range shifl for control module on Templifier
units.
Capacity Control
Solenoid
SA None
None Lube
BOX
Module Part of 4-way solenoid valve. When energized, applies full oil pressure
Red
on control piston and closes vanes-UNLOAD.
Capacity Control
Solenoid
SB None
None Lube
BOX
Module Part of
4-way
solenoid valve. When energized, applies full oil pressure
Green
on control piston and opens vanes-LOAD.
Starts Counter
SC None
None Panel None
Counts number of compressor starts
Surgegard Relay
SGR
Non-
Adiust.
Auto/Man
Relay
Section
Surgegard Works with thermistor to sense impeller cavity temperature. Protects
compressor from a surae
(CEO63
thru 126).
System Monitor
Timer
SM 60 sec.
Auto/Man
Relay
Ext. Fail
If compressor fails to start in 60 seconds after system monitor
IS
Section
energized, system monitor terminates start effort.
Sump Oil
Thermostat
SOT
104°F
Auto
Control
Box
None
On units with refrigerant cooled oil cooler, controls oil sump heater to
maintain set temperature.
Sequence Relay
SR None None Field
Suoolied
None
Relay controlled by system thermostat (or other control) to start unit
on call for
cooling.
Source Water
Thermostat
SWT
Field Set Auto
Temp.
Section
Load
Stop compressor when water temperature entering evaporator is too
Recycle
low for practical heat recovery.
Anti-Recycle Time
Delay Relay
Transition Resistor
Protector
TDR
TRP
20 Min.
None
Relay None
Prevents compressor from restarting for 20 minutes after previous
Section
shutdown.
None
Auto/Man
Starter
Ext. Fail
Abort compressor starting sequence if starter fails to make transition
from star to delta within 1 second.
Pilot Expanasion
Valve Solenoid
Vane Closed
Switch
Vane Delay
Contacts
TXS
vc
VD
None
40 psig
Differential
None
None
None
None
Piping
Lube
Box
Starter
None
Opens when 2nd compressor starts, closes when 2nd compressor
stops (PF063 only).
Oil
Prevents compressor starting unless capacity control vanes are closed
Press.
(fully unloaded).
None
Auxiliary contacts in compressor starter prevent compressor loading
and liquid solenoid valves from opening (SEH units only) until com-
pressor motor connected across the line.
Voltage Relay
VR Non-
Adjust.
None Lube
Box
None
Disconnects
oil
pump motor capacitor after start (CEO50 only).
NOTE
#1
Auto-This control automatically resets itself.
Manual-This control requires manual reset which is done mechanically with RESET button
Auto/Man-This control automatically resets itself but electrical lockout circuit requires that RESET button be pushed to reset the circuit.
NOTE #2
This table contains all standard and most optional control components used in McQuay
centrifugals.
All listed controls are not necessarily used on all units
Controls for specific units can be identified by referring to control diagram and/or the unit control center.
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