Sequence of Operation Chapter 4
750-177 4-9
PCR Pump Control Relay
PFCC Power Factor Correction Capacitor
PFFL Pilot Flame Failure Light
PFFR Pilot Flame Failure Relay
PFPS Positive Furnace Pressure Switch
PHGPS Pilot High Gas Pressure Switch
PIPL Purge in Progress Light
PIS Pilot Ignition Switch
PLC Programmable Logic Controller
PLGPS Pilot Low Gas Pressure Switch
POL Power On Light
POV Pilot Oil Valve
PPL Pre-Purging Light
PPR Post Purge Relay
PPTD Post Purge Time Delay
PR Program Relay
PRL Purge Ready Light
PRPTD Pre-Purge Time Delay
PR Program Relay
PRPTD Per-Purge Time Delay
PS Power Supply
PSF Power Supply Fuse
PSS Pump Selector Switch
PSV Purge Solenoid Valve
PT Purge Timer
PTS Pump Transfer Switch
PUCR Purge Complete Relay
PUR Purge Relay
R
R Red (Color of Pilot Light)
RAR Remote Alarm Relay
RATD Remote Alarm Time Delay
RES Resistor
RML Run Mode Light
RMR Release To Modulate Relay
RS Range Switch
RSR Remote Start Relay
RTD Resistance Temperature Detector
S
SBFPL Stand By Feed Pump Light
SBFPM Stand By Feed Pump Motor
SBFPMCB Stand By Feed Pump Motor Circuit Breaker
SBFPMF Stand By Feed Pump Motor Fuses
SBFPMS Stand By Feed Pump Motor Starter
SBOV Surface Blow Off Valve
SBPS Sootblower Pressure Switch
SBR Sootblower Relay
SC Scanner
SCTS Supervisory Cock Test Switch
SDL Steam Demand Light
SHT Steam Heater Thermostat
SHV Steam Heater Valve
SLCL Safety Limits Complete Light
SPIR System Pump Interlock Relay
SPS Steam Pressure Sensor
SS Selector Switch
Table: 4-1 Electrical Nomenclature (Continued)
MNEMONIC DESCRIPTION
SSC Sequencing Step Controller
SSL Safety Shutdown Light
SSR Solid State Relay
SSV SpanSolenoid Relay
STHWC Surge Tank High Water Control
STHWL Surge Tank High Water Light
STHWR Surge Tank High Water Relay
STLWC Surge Tank Low Water Control
STLWL Surge Tank Low Water Light
STLWR Surge Tank Low Water Relay
T
(T.C.) Timed Closed
(T.O.) Timed Open
TB Terminal Block
T/C Thermocouple
TC Time Clock
TCR Time Clock Relay
TD Time Delay
TDAS Time Delay Auxiliary Switch
TFWR Transistorized Feedwater Relay
TPL Transfer Pump Light
TPM Transfer Pump Motor
TPMCB Transfer Pump Motor Circuit Breaker
TPMF Transfer Pump Motor Fuses
TPMS Transfer Pump Motor Starter
TPS Transfer Pump Switch
U
UVFD Ultra-Violet Flame Detector
V
V Voltmeter
VDR Voltage Differential Relay
W
W White (Color of Pilot Light)
WC Water Column
WCBDS Water Column Blow Down Switch
WF Water Feeder
WFNL Water Flow Normal Light
WLC Water Level Control
WO Denotes Waste Oil Equipment (Prefix)
WTS Water Temperature Sensor
Y
Y Yellow (Color of Pilot Light)
Table: 4-1 Electrical Nomenclature (Continued)
MNEMONIC DESCRIPTION