204 South Sixth Avenue, Mansfield, TX   76063
Phone: 1-817-473-9964
Toll Free: 1-800-222-3710
Fax: 1-817-473-0606

Product Name: Water-Powered Oscillating Monitors

CHEMGUARD COM-HD Water-Powered Oscillating Monitor assemblies are designed to automatically oscillate over a preset arc upon system activation, allowing discharge over a wide design area without manual intervention or the use of electrical power. This device is intended for use in firefighting foam systems designed in accordance with NFPA 11, NFPA 409, and/or NFPA 418, typically found in high risk areas such as tank farm facilities, refineries, aircraft hangars, and heliports.


The CHEMGUARD COM-HD water-powered oscillating unit is designed for use with any 3 in. water way manual monitor equipped with a standard 4 in. ANSI Class 150 flange inlet connection. When the monitor is connected to the oscillating unit, the monitor operates as an automatic water-powered oscillating monitor.

The heavy duty stainless steel swivel bearing and all stainless steel design of the body provide exceptional durability and corrosion-resistance for applications requiring long, continuous or repeated use in normal and harsh environments.

The innovative swivel bearing design (patent pending) allows for easy field replacement of only the bearing, in the unlikely event that the bearing wears out or is damaged through misuse or improper maintenance.

  • The COM-HD is UL listed when sold as an assembly with the 3 in. BRAHMA monitor and CMNB350, CMNB500, or CMNB750 fixed flow monitor nozzle with 2-1/2 NHT connections. Refer to the UL Product IQ for foam concentrate
    • specific flow and pressure ranges.
  • The COM-HD Oscillating Base Unit is FM Approved for use with water when used in conjunction with FM Approved Monitor and Nozzle assemblies. Refer to for specific flow and pressure ranges.
  • Materials of construction:
    • 304 Stainless Steel: Bearing, main body, connection flanges, linkage assembly, oscillator housings
    • Bronze: Water drive wheel, speed control valve, automatic drain valve
    • Brass: Check valve, test connection (garden hose adaptor)
  • Suitable for use with most foam solutions.
  • Arc of oscillation adjustable via six set points
    • 25, 40, 60, 80, 100, and 120 degrees
  • Speed of oscillation is adjustable using the speed adjustment valve. Maximum speed is approximately 40 deg/sec. Speed may vary when switching from water flow to foam solution flow at same valve adjustment setting.
  • Manual override capabilities in horizontal and vertical degree fields when purchased as an oscillating monitor assembly.
  • Operating inlet pressure: Minimum 40 psi (2.8 bar) Maximum 200 psi (14 bar)
  • Maximum flow rate 1250 gpm, with BRAHMA monitor.
  • Double reduction oil bath gearbox.
  • Standard grease zerk fittings for easy maintenance.
  • Single tiller bar for positioning and control of the monitor.
  • Oscillating monitor includes hose test connection for a functional check of the unit without flowing the system.
  • Drain valve automatically drains oscillator base piping after system shutoff, to help provide cold weather protection.


A water drive wheel connected to a double reduction gearbox drives the oscillating monitor. To operate the drive wheel, a small flow, not exceeding 13 gpm at maximum recommended oscillation speed, is diverted from the monitor inlet. The monitor requires no external wiring or hydraulic control for operation. The vertical angle of elevation and horizontal arc of oscillation is field adjustable and can be set and locked in position. The monitor can be set to oscillate over a range of 0° to 120° and the location of the oscillation arc may be set anywhere within the 360° field of operation. Elevation range of the unit is between 65° and -20°.

The CHEMGUARD COM-HD unit is available in three different configurations.

Configuration Description
1 Oscillating Base Unit: Oscillating Unit only, standard 4 in. ANSI Class 150 inlet and outlet flange connections
2 Oscillating Monitor Assembly: Oscillating Unit complete with assembled 3 in. BRAHMA Monitor and choice of fixed flow nozzle with 2-1/2 NHT nozzle connections.
3 Oscillating Base Unit with externally sourced Monitor and Nozzle: Oscillating Base Unit packaged with externally sourced monitor and nozzle options (may increase lead times).


Product NameWater-Powered Oscillating Monitors
Product #COM-HD


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