microFLEX M2B Controller

Single Boiler/Condensate Controller

The ProMinent® microFLEX is a powerful controller integrating built-in diagnostics with realtime monitoring in a compact design.

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Standard Features

  • Boiler or Condensate Conductivity input
  • Single water meter input
  • Boiler status input
  • Chemical feed relay
  • 5 Key universal keypad
  • 2 Line, 16 character backlit display
  • Boiler blowdown or condensate diverter relay (solenoid valve or motorized ball valve)


  • Selectable chemical feed mode: Provides 3 feed modes; feed on volume, blowdown & feed and percentage time.
  • Conductivity control: Can be programmed using timed or continuous sampling.
  • Water meter input: Allows for chemical to be fed based on water volume versus timed pump control methods generally found on comparably priced controllers.
  • What and Why Information: Diagnostics shown on display are a valuable troubleshooting tool. Conductivity valve and chemical pump relays show complete stauts. Shows WHY the relay is on/off.
  • Single point calibration: For ease of start up and operation. Warning message immediately detects foulled or faulty sensors.
  • Controller run time: Gives total hours per day and total operating days since initial installation.
  • Robust diagnostics: Provides complete 24 hour history of blowdown valve operation and chemical relay timing intervals.
  • Keypad password: Eliminates unauthorized adjustments.
  • Communication options: Includes Ethernet networking, dry contact alarm relay or 4-20mA output on conductivity.
  • Optional web browser user interface with networking capability: Provides ability to direct connect to the controller from a portable workstation, such as a laptop computer. Can also view critical processes remotely through the use of a LAN.

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Rating - Detail Notes
Analog-Digital I/O
Conductivity Sensor Auto ranging from 100uS to 10,000uS, rated 250psi Single point calibration
Water Meter Input current 400Hz, 0.5mA @ 5VDC measurement head Accepts paddlewheel or contacting
Relay Outputs 1 SPDT (Bleed) 1 SPST (Chemical feed), valve Powers either solenoid or motorized
4-20mA Output (optional) Single DC isolated, loop powered loop User definable span, alarms on open
Alarm Relay (optional) 500mA @ 24VDC Dry contact set, unfused Normally closed contact, open on alarm
Communications User Interface
Keypad-LCD 5 Key tactile feedback, universal characters, 2 line x 16 character, backlit Scan rate 100 mS nominal, User adjustale contrast
10 Base T, TCP/IP Ethernet LAN (optional) HTML micro web server with user definable IP address Static IP, Use browser to see I/O, edit program
Relay ON/OFF Captured sample & ON/OFF control valve Relay 1 chemical feed, Relay 2 bleed
Volumetric feed User set, measure volume & pump on time
Interlocking Contact set input Blowdown & feed stop
Alarms - Feed Limit Timers Minutes per day Auto-reset @ Midnight
Electrical 120VAC, 60Hz
Fusing 5 AMPS @ 120VAC
Surge Suppression Relay 2 N.O. contacts snubbed @ 0.1uF, 150ohm Varistor on AC line input
Accessory Power fused @ 50mA 15-22VDC, unregulated, thermally
Enclosure Non-metallic, NEMA 4X 5.9”W x 5.9”H x 3.5”D (150mmW x 150mmH x 90mmD)
CSA, CE, UL CSA tested to comply with UL


Download Zip File With Controller Accessory Documents | Part #: xxxxxx | Updated: 4/2/14

Application Notes

Application Notes: "Snubber" Explanation | Part #: xxxxxx | Updated: 5/29/13
Boiler Blowdown Conductivity Tracking | Part #: xxxxxx | Updated: 4/18/06
How To Setup Computer IP Address | Part #: xxxxxx | Updated: 10/12/12

Boiler & Cooling Tower Instructional Videos

Video: Cooling Tower & Boiler Controllers II: Communication Options (WEBINAR) | Part #: xxxxxx | Updated: 1/24/14
Video: Inputs/Outputs & Hardware For Boiler & Cooling Tower Controllers (WEBINAR) | Part #: xxxxxx | Updated: 11/8/13


Cut Sheet: MicroFLEX Single Boiler/Condensate | Part #: 7750302 | Updated: 8/17/21


Trackster | Part #: Version 3.2.5385 | Updated: 10/22/14

Installation And Wiring

Cradlepoint CTR500 Setup | Part #: xxxxxx | Updated: 7/19/13

Product Catalog Full Version

Catalog: 2023 Product Catalog - Full Version | Part #: 7750257 | Updated: 3/3/23

Product Catalog Section

Catalog: 2023 Product Catalog - Pumps & Systems Accessories Section | Part #: 7750257 | Updated: 3/3/23
Catalog: 2023 Product Catalog - DULCOMETER, Cooling Tower & Boiler Controller Section | Part #: 7750257 | Updated: 3/3/23

ProMinent Helps Video

Video: ProMinent & Cranberry Township Wastewater Treatment Plant | Part #: xxxxxx | Updated: 4/10/19

Sensor Instructional Videos

Video: Changing Electrolyte In Sensors | Part #: xxxxxx | Updated: 7/28/21

Sensor Specifications

MicroFlex Boiler - Condensate | Part #: xxxxxx | Updated: 4/2/14

Technical Manual

Technical Manual: Boiler Sensor Test Procedure | Part #: xxxxxx | Updated: Unknown
Technical Manual: How To Connect To Controllers | Part #: xxxxxx | Updated: Unknown
Technical Manual: How To Connect To Controllers (Power Point) | Part #: xxxxxx | Updated: Unknown
Technical Manual: How To Setup Computer IP Address | Part #: xxxxxx | Updated: 10/12/12
Technical Manual: How To Setup Computer IP Address (Power Point) | Part #: xxxxxx | Updated: Unknown
Technical Manual: Optional Wireless Communications EvDO | Part #: 7750312 | Updated: 6/27/13
Troubleshooting Via Hyper Terminal | Part #: xxxxxx | Updated: 1/1/09
Troubleshooting Via Hyper Terminal (Power Point) | Part #: xxxxxx | Updated: 1/1/09