Brooks Instrument High-Flow PTI Thermal Mass Flow Controller
About this part
The Brooks Instrument GF126 is the high-performance, high-flow, pressure-transient-insensitive model in the GF100 Series. Its documented model envelope is 55–300 slm nitrogen equivalent, with integrated inlet-pressure measurement and a 5 µin Ra ultra-high-purity wetted flow path. Gas, full-scale range, valve state, fitting, downstream condition, communications interface, and customer options are established by the complete configured code rather than GF126 alone
Configurations vary. Verify the exact unit before choosing a replacement.
Application classSemiconductor/high-purity gas delivery
CategoryFlow Control
Specifications
Identification
Manufacturer
Brooks Instrument
Product series
GF100 Series
Model role
High-performance, high-flow model with pressure transient insensitivity (PTI)
Flow
Full-scale model envelope
55–300 slm nitrogen equivalent; the installed full-scale range requires the complete configured code or calibration label
MultiFlo range bins
Applicable configurable builds use high-flow bins SH51 through SH54; gas-specific and non-configurable builds are also defined by the ordering structure
Performance
Flow accuracy
±1% of set point over 35–100% full scale and ±0.35% of full scale over 2–35%, based on factory nitrogen calibration
Repeatability and reproducibility
Less than ±0.15% of set point
Settling time
Less than 1 second with a normally closed valve
Control range
5–100% full scale with a normally closed valve
Pressure transient capability
Manufacturer ordering instructions identify GF126 as the high-flow PTI model; its package includes integrated inlet-pressure measurement
Pressure
Differential-pressure range
30–90 psid
Maximum operating pressure
75 psig for a controller configuration; the documented meter limit is 150 psig
Environment
Operating temperature
10–50 °C
Materials
Wetted-flow-path context
5 µin Ra ultra-high-purity flow path in the current analog/DeviceNet data sheet and July 2026 installation manual; wetted materials are documented as SEMI F20 HP compliant and configuration dependent
Controls
Communication options
Analog/RS-485, DeviceNet, and EtherCAT configurations are documented; the installed interface requires the complete connector code
Mechanical
Connection options
Model-code options include 1/2-inch VCR male and 3/8-inch C-Seal configurations; the exact fitting cannot be inferred from GF126 alone
What Does GF126 Mean?
GF126 decodes only the platform and package/finish segments. It does not identify the complete unit configuration.
Segment
Field
Interpretation
GF
Base model code
Brooks high-purity/ultra-high-purity digital mass-flow controller platform
126
Package / finish
High-flow 55–300 slm nitrogen-equivalent package with a 5 µin Ra ultra-high-purity wetted flow path, integrated pressure measurement, and PTI positioning
Configuration Boundaries
GF126 alone does not establish configurability, gas, calibrated full-scale range, valve or meter selection, fitting, downstream condition, connector, communications protocol, customer-special requirement, auto-shutoff option, or reference temperature.
A complete order code, calibration certificate, or readable physical label is required before asserting those configured-unit details.
The archived 100 slm nitrogen, DeviceNet, and 3/8-inch C-Seal description applies only to the observed unit.
