How to Read a P&ID - Pressure Control

This drawing demonstrates a pressure control loop for a hot water storage vessel (V-100). The pressure inside the vessel is regulated via a split-range pressure controller (PIC-101) which commands control valves to either introduce nitrogen gas for pressurization or vent excess gas to a vent line. The vessel is also equipped with temperature and level indication systems.

Source: images.png · Drawing: P&ID Drawings 101 - Corso Systems Training rev 17 · Components: 13 (2 equipment, 8 instrument, 3 valve)

Equipment (2)

Tag Description Details Connects to
V-100 Hot Water Storage Tank HOT WATER STORAGE HEAT PAD, TT 102, LG 2, LT 100, V-1, V-2, PRV-1, PY 101A, PY 101B
HEAT PAD Heat Pad — V-100, TIC 102

Instruments (8)

Tag Function (ISA 5.1) Description Details Connects to
PY 101A PY = Pressure Solenoid / Converter, Loop 101A Nitrogen Control Valve and Actuator — V-100, PIC 101
PY 101B PY = Pressure Solenoid / Converter, Loop 101B Vent Control Valve and Actuator — V-100, PIC 101
PIC 101 PIC = Pressure Indicating Controller, Loop 101 Pressure Indicating Controller — PY 101A, PY 101B
TT 102 TT = Temperature Transmitter, Loop 102 Temperature Transmitter — V-100, TIC 102
TIC 102 TIC = Temperature Indicating Controller, Loop 102 Temperature Indicating Controller — TT 102, HEAT PAD
LG 2 LG = Level Gauge, Loop 2 Level Gauge — V-100
LT 100 LT = Level Transmitter, Loop 100 Level Transmitter — V-100, LI 100
LI 100 LI = Level Indicator, Loop 100 Level Indicator — LT 100

Valves (3)

Tag Description Details Connects to
V-1 Hot Water Inlet Globe Valve Normally Closed (N.C.) V-100
V-2 Outlet Globe Valve Normally Closed (N.C.) V-100
PRV-1 Pressure Relief Valve Vents directly to atmosphere/vent line V-100

Notes on drawing