MKS Mass-Flo 1159B - User Manual

Questions and Answers

M
Miguel RiggsAug 14, 2025
Why is my MKS Controller oscillating?
- D
  Danielle YuAug 15, 2025
  Oscillation in the MKS Controller can occur due to several reasons: * Too high a controller gain setting: Reduce the gain by turning it counterclockwise. * Incorrect upstream pressure regulator: Check the manufacturer's specifications for the regulator. * Upstream pressure too high: Reduce the upstream pressure. * Amplifier not handling capacitance loads: Install a 150 to 1000 ohm resistor in series with the set point input line.
R
rclarkAug 18, 2025
What to do if MKS Controller does not track set point?
- A
  Austin TaylorAug 18, 2025
  If your MKS Controller isn't tracking the set point, it might be due to improper zero adjustment. To resolve this, zero the meter output as described on page 26.
C
Catherine FisherAug 21, 2025
Why MKS Mass-Flo 1159B indicates approximately twice the known flow and is unstable?
- A
  albert16Aug 21, 2025
  If the MKS Controller indicates approximately twice the known flow and is unstable, it is because the unit is installed backwards in the gas stream. Reinstall the unit in the proper flow direction to fix this.
K
kelly66Aug 25, 2025
Why MKS Controller unit exhibits a large zero temp coefficient?
- D
  Dr. Marissa GonzalezAug 25, 2025
  If the MKS Controller unit exhibits a large zero temperature coefficient, the ambient heater might be out of regulation. Check the placement of the flow meter in the hot system. Return for service.
G
gthompsonAug 28, 2025
What to do if MKS Mass-Flo 1159B does not function?
- C
  Christina ReedAug 28, 2025
  If the MKS Controller does not function, the electronics might be malfunctioning. Disconnect the valve override and return for service.
S
smithstephanieAug 31, 2025
What to do if MKS Mass-Flo 1159B Controller has no output or over-range at zero after warm-up?
- D
  David NelsonAug 31, 2025
  If the MKS Controller shows no output or an over-range at zero after warm-up, the electronics might be malfunctioning. Check the cable type and return for service.
D
Dylan SampsonSep 4, 2025
Why MKS Controller unit produces a large pressure drop or will not pass full flow?
- J
  Joe JenkinsSep 4, 2025
  If the MKS Controller unit produces a large pressure drop or will not pass full flow, it could be due to a clogged sensor tube and/or bypass. Return for service.
C
charles68Sep 7, 2025
Why MKS Controller over-ranges at zero after warm-up?
- L
  lkiddSep 7, 2025
  If the MKS Controller over-ranges at zero after warm-up, it might be because the sensor winding is open. Isolate the MFC and return for service.
M
Michael Miller IIISep 12, 2025
Why MKS Mass-Flo 1159B unit is non-linear or has erratic operation?
- S
  Shannon KingSep 12, 2025
  If the MKS Controller unit is non-linear or has erratic operation, the winding might be out of regulation. Return for service.

Summary

Warranty

Safety Procedures and Precautions

Chapter Two: Installation

How To Unpack the 1100 Series Unit

Provides instructions for checking and unpacking the Type 1100 Series MFC unit.

Setup

Chapter Three: Overview

General

Electrical Connections

Describes the pinouts for Type 'D' and P. C. Edge Card connectors.

Control Valve

Chapter Four: Operation

Warm Up and Start Up

Details the procedures for starting up and warming up the flow controller.

How To Start Up the Flow Controller

Step-by-step guide to powering up and connecting the MFC to a system.

How To Zero the Flow Controller

Procedure for zeroing the flow controller to ensure accurate readings.

Adjust the Zero Pot

Chapter Five: Theory of Operation

Flow Path

Measurement Technique

Describes the principle of maintaining temperature profiles for mass flow measurement.

Control Circuitry

Gas Correction Factor

Explains how to use the Gas Correction Factor for gases other than nitrogen.

How To Determine the Flow Controller Range

Chapter Six: Maintenance

Valve Adjustment

Provides steps to adjust the control valve for optimal performance and leak detection.

Repair

Chapter Seven: Troubleshooting

Troubleshooting Chart

A chart listing symptoms, possible causes, and remedies for common MFC issues.

MKS Mass-Flo 1159B Specifications

General

Type	Mass Flow Controller
Gas Compatibility	Various gases (specific gases depend on model configuration)
Flow Rate Range	0-5 SCCM to 0-500 SLM (varies by model)
Accuracy	±1% of full scale
Repeatability	±0.25% of full scale
Response Time	<1 second to 90% of setpoint
Control Stability	±0.1% of full scale
Operating Pressure	Up to 150 psig (10.3 barg)
Operating Temperature	0°C to 50°C (32°F to 122°F)
Control Signal	0-5 VDC or 4-20 mA
Output Signal	0-5 VDC or 4-20 mA
Process Connection	1/4" Swagelok® or compatible fittings. Consult specific model datasheet.
Measurement Range	0-5 SCCM to 0-500 SLM (varies by model)