---
title: "How to Read a P&ID - Pressure Control — asset register"
doc_type: pid-asset-register
drawing_number: "Page 17"
source: "images.png"
tags: [V-100, HEAT PAD, V-1, V-2, PY-101A, PV-101A, PIC-101, PY-101B-1, PY-101B-2, PV-101B, PSV-1, TT-102, TIC-102, LG-2, LT-100, LI-100]
summary: "This P&ID illustrates a pressure control loop for a Hot Water Storage vessel (V-100). Pressure is controlled via a split-range controller (PIC-101) which regulates nitrogen supply (PY-101A) and pressure venting (PY-101B). Temperature is maintained via a heat pad controlled by TIC-102, and level is monitored by level transmitter LT-100 and level gauge LG-2."
---

# How to Read a P&ID - Pressure Control

This P&ID illustrates a pressure control loop for a Hot Water Storage vessel (V-100). Pressure is controlled via a split-range controller (PIC-101) which regulates nitrogen supply (PY-101A) and pressure venting (PY-101B). Temperature is maintained via a heat pad controlled by TIC-102, and level is monitored by level transmitter LT-100 and level gauge LG-2.

**Source:** images.png · **Drawing:** Page 17 · **Components:** 16 (2 equipment, 9 instrument, 5 valve)

## Equipment (2)

| Tag | Description | Details | Connects to |
|---|---|---|---|
| V-100 | Hot Water Storage | Service: Hot Water Storage | V-1, V-2, TT-102, LG-2, LT-100, PV-101A, PV-101B, PSV-1, PY-101B-2 |
| HEAT PAD | Heat Pad | — | TIC-102 |

## Instruments (9)

| Tag | Function (ISA 5.1) | Description | Details | Connects to |
|---|---|---|---|---|
| PY-101A | PY = Pressure Solenoid/Relay/Converter, Loop 101A | Pressure Solenoid/Relay/Converter | — | PIC-101, PV-101A |
| PIC-101 | PIC = Pressure Indicating Controller, Loop 101 | Pressure Indicating Controller | — | PY-101A, PY-101B-1, PY-101B-2 |
| PY-101B-1 | PY = Pressure Solenoid/Relay/Converter, Loop 101B | Pressure Solenoid/Relay/Converter (Top) | — | PIC-101, PV-101B |
| PY-101B-2 | PY = Pressure Solenoid/Relay/Converter, Loop 101B | Pressure Solenoid/Relay/Converter (Middle) | — | PIC-101, V-100 |
| 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 Glass, Loop 2 | Level Glass / 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 (5)

| Tag | Description | Details | Connects to |
|---|---|---|---|
| V-1 | Isolation Valve | N.C. (Normally Closed) | V-100 |
| V-2 | Isolation Valve | N.C. (Normally Closed) | V-100 |
| PV-101A | Pressure Control Valve | — | PY-101A, V-100 |
| PV-101B | Pressure Control Valve | — | PY-101B-1, V-100 |
| PSV-1 | Pressure Safety Relief Valve | Vents directly to atmosphere/vent line | V-100 |

## Notes on drawing

- P&ID Drawings 101 - Corso Systems Training
- N.C. = Normally Closed