*H

Here’s a list of Instrumentation abbreviations starting with the letter “H”, commonly used in P&IDs, datasheets, control systems, and field instrumentation.

H: High / Heater / Hydraulic (context dependent)
HA: High Alarm
HAC: High Alarm Controller
HAH: High Alarm High
HAL: High Alarm Low
HAM: High Alarm Module
HAP: Hydraulic Actuator / Heater Assembly
HAS: High Alarm Switch
HB: Hand Brake / Hydraulic Brake
HBC: Hydraulic Brake Controller
HBD: High Blowdown
HBV: Hydraulic Block Valve
HC: Hand Controller / Heater Control
HCA: Heater Control Assembly
HCC: Heater Control Cabinet
HCD: Heater Control Device
HCM: Heater Control Module
HCP: Heater Control Panel
HCS: Hydraulic Control System
HD: Hydraulic Drive / High Differential
HDC: Hydraulic Drive Controller
HDD: Hard Disk Drive (control system related)
HDI: High Differential Indicator
HDL: High Differential Limit
HDP: Hydraulic Design Pressure
HE: Heat Exchanger / Heating Element
HEA: Heater Assembly
HEC: Heater Element Controller
HEM: Heater Element Module
HES: Heater Electrical Supply
HF: High Frequency / Hydraulic Fluid
HFA: Hydraulic Fluid Alarm
HFC: Hydraulic Flow Controller
HFD: Hydraulic Flow Device
HFM: Hydraulic Flow Meter
HG: High Gauge / Hydraulic Gauge
HGC: Hydraulic Governor Controller
HH: High High
HHA: High High Alarm
HHC: High High Controller
HHD: High High Device
HHI: High High Indicator
HHL: High High Limit
HHS: High High Switch
HHT: High High Transmitter
HI: Hand Indicator / High Indicator
HIC: Hand Indicating Controller
HIM: Human Interface Module
HLA: High Level Alarm
HLC: High Level Controller
HLI: High Level Indicator
HLL: High Level Low
HLS: High Level Switch
HLT: High Level Transmitter
HM: Hydraulic Motor / Hand Mode
HMI: Human Machine Interface
HMP: Hydraulic Motor Pump
HN: High Noise
HO: Hand Operated
HOC: Hand Operated Controller
HP: High Pressure / Horsepower
HPC: High Pressure Controller
HPD: High Pressure Detector
HPI: High Pressure Indicator
HPL: High Pressure Limit
HPS: High Pressure Switch
HPT: High Pressure Transmitter
HR: Heater / Hour
HRC: Heater Relay Controller
HRS: Heater Reset Switch
HS: Hand Switch / High Speed
HSC: High Speed Controller
HSD: High Speed Drive
HSI: High Speed Indicator
HSL: High Speed Limit
HSS: High Speed Switch
HT: High Temperature / Heater Transformer
HTC: High Temperature Controller
HTD: High Temperature Detector
HTI: High Temperature Indicator
HTL: High Temperature Limit
HTS: High Temperature Switch
HTT: High Temperature Transmitter
HU: Hydraulic Unit
HV: Hand Valve / High Voltage
HVC: Hand Valve Controller / High Voltage Controller
HVG: High Voltage Generator
HW: Hot Water
HWP: Hot Water Pump
HX: Heat Exchanger