---
title: "How to Read a P&ID - Pressure Control — asset register"
doc_type: pid-asset-register
drawing_number: "P&ID Drawings 101"
source: "images.png"
tags: [V-100, HEAT PAD, V-1, V-2, PY-101A, PIC 101, PY 101B, PY 101B (lower), relief-valve-1, TT 102, TIC 102, LG 2, LT 100, LI 100]
summary: "This diagram illustrates pressure and temperature control loop concepts on a hot water storage tank (V-100) equipped with an external heat pad. A pressure indicating controller (PIC 101) manages the tank's internal pressure by split-ranging a nitrogen supply control valve and a vent control valve, while a temperature loop monitors and regulates the heating pad."
---

# How to Read a P&ID - Pressure Control

This diagram illustrates pressure and temperature control loop concepts on a hot water storage tank (V-100) equipped with an external heat pad. A pressure indicating controller (PIC 101) manages the tank's internal pressure by split-ranging a nitrogen supply control valve and a vent control valve, while a temperature loop monitors and regulates the heating pad.

**Source:** images.png · **Drawing:** P&ID Drawings 101 · **Components:** 14 (2 equipment, 9 instrument, 3 valve)

## Equipment (2)

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

## Instruments (9)

| Tag | Function (ISA 5.1) | Description | Details | Connects to |
|---|---|---|---|---|
| PY-101A | PY = Pressure Solenoid/Converter, loop 101A | Pressure Solenoid Valve | — | PIC 101, V-100 |
| PIC 101 | PIC = Pressure Indicating Controller, loop 101 | Pressure Indicating Controller | — | PY-101A, PY 101B, PY 101B (lower) |
| PY 101B | PY = Pressure Solenoid/Converter, loop 101B | Pressure Solenoid Valve | — | PIC 101, V-100 |
| PY 101B (lower) | PY = Pressure Solenoid/Converter, loop 101B | Pressure Relay | — | 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 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 | Normally Closed Valve | N.C. | V-100 |
| V-2 | Normally Closed Valve | N.C. | V-100 |
| relief-valve-1 | Pressure Relief Valve | Vents to atmosphere | V-100 |

## Notes on drawing

- Corso Systems Training
- Slide 17