Portalevel® MAX PLUS

Advanced Ultrasonic Liquid Level Indicator for Fire Cylinders

Portalevel® MAX PLUS is our latest high-spec UL listed addition to our line of handheld, battery powered liquid level indicators. With Portalevel® MAX PLUS, an operator can rapidly and reliably detect the liquid level within a fire cylinder, with clear GAS / LIQUID interface, with an accuracy of ±1.5mm in under 30 seconds.

P/N: 2290334-COMXPS
NSN: 6625-99-257-8336
IMPA MSG P/N: 652776


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Delivering Safesite® and Ensure Asset & Personnel Safety

Portalevel® MAX PLUS is the latest addition to our range of ultrasonic liquid level indicators as part of our Safesite® mission. Safesite® aims to minimise loss in industrial environments by ensuring a facility’s safe operation in the most efficient way. By complying with ISO and NFPA requirements through precision and speed, Portalevel® MAX PLUS provides a much more convenient and reliable method of fire agent contents monitoring than traditional weighing. This is because Portalevel® MAX PLUS is:

Non-Invasive: The cylinder is not compromised and no manual weighing is required

Precise & Fast: A single operator can reliably measure numerous cylinders with an accuracy of  ±1.5mm in under 30 seconds per cylinder

Adaptable: With 3 calibration modes and 4 power settings, Portalevel® MAX PLUS can be adjusted to reliably measure different cylinder types and sizes

Robust: With an IP65 enclosure and backlit LCD display, the unit can be easily operated in challenging and poorly-lit industrial environments


Agent Weight Calculation with Portasteele®

The combination of the Portalevel® MAX PLUS and Portasteele® CALCULATOR uses our decades of experience in ultrasonic engineering and collaboration with fire suppression system manufacturers to allow a user to clearly determine the agent weight from the liquid level without having to physically weigh the cylinder. The benefits of this are:

Tracebility: The liquid level found is traceable to the agent weight which is the only documented evidence of fire suppression cylinder contents from the manufacturer

Temperature Correction: Any fluctuations in liquid level as a result of temperature changes is automatically accounted for in the calculations, giving you the true agent contents at all times regardless of temperature


All measurements are saved and recorded with time & date stamp, for effectively audit trail and to comply with relevant ISO and NFPA regulations where agent weight is required to be reported


Simple Yet Effective

Portalevel® MAX PLUS’s exceptional accuracy is matched only by its ease of use.

  1. An ultrasonic pulse is emitted by Portalevel® MAX PLUS’s transducer into the cylinder.
  2. The signal is reflected, returned, and analysed to determine if the contents at that level are a liquid or gas.
  3. After pressing the CAL button, the sensor can be moved up or down the cylinder to accurately find the liquid/gas boundary. This process can take under 30 seconds with a skilled operator.


What's In The Box

  Portalevel® MAX PLUS :Main Unit
  Handheld Ultrasonic Sensor:For transmitting ultrasound
  Ultrasonic Couplant:Ensure good contact between cylinder and sensor
  Infrared Thermometer:To measure cylinder surface temperature
  Operating Instructions:Provide guidance on how-to-use
  Calibration Certificate:Certify unit has been tested successfully
  Robust Carrying Case:To hold the equipment and accessories

Technical specifications

Technical Specification

167x82x30 mm (L x W x D)

Unit Weight

300g (with batteries)


±1.5 mm (±1/16 inch)

Sensor Type

14mm diameter magnetically mounted

Sensor Frequency

1 MHz

Sensor Connectivity

1 m BNC coaxial cable.

Power Supply

1 x PP3 9V battery

Battery Life

10 hours continuous use


55 x 28 mm backlit LCD

Operating Temperatures

-10 °C to +65 °C (14 °F to 149 °F)

IP Rating

IP65 Rating (Enclosure)

Classifications & Approvals

UL Listed, RINA Classification Society Approval


CE, UKAS, Coltraco is ISO 9001 and ISO 14001 registered

  • Main Unit: 3-Year Warranty  
  • Sensor: 1-Year Warranty  
  • Technical Support: Lifetime of the unit 

See the Portalevel® MAX PLUS in action.

Frequently asked questions

The Portalevel® MAX PLUS can measure the level of a wide variety of liquids. The primary application is for checking the liquid level in fire suppression cylinders. These agents commonly include: CO2, FM200™, NOVEC™ 1230, Halon agents, FE-13™, FE-25™, NAF S III™ and, all core Clean Agent systems. However, the Portalevel® MAX PLUS has been shown to work on other liquids such as water, fuel, LPG and even mayonnaise in the processed food industry.
The Portalevel® MAX PLUS can identify the liquid level to ±1.5 mm of the actual liquid level. When using the Portasteele® CALCULATOR to convert the liquid level to agent weight, the results are accurate to within 1%.
CAL1 – This is the standard setting to be used in most cases. This will work when the trend in readings you observe go from high to low with a large drop-off (see annex for explanation) CAL2 – This mode is to be used when the difference between high and low readings is great, or if CAL 1 is insufficient. CAL3 – This mode is to be used when the difference between high and low readings is small, and/or CAL 1 or 2 is insufficient.
The Portalevel® MAX PLUS is one of the most powerful we have developed and works on a large range of cylinder sizes. We have an extensive range of products that can measure anything from 10 cm to over 15 m diameter, so get in touch to find out which unit is suitable for your application.
No, you can use any ultrasonic gel, available in most pharmacies, as well as petroleum jelly. Water will also work, but in hot environment needs very regular application.
No, unfortunately above this temperature CO2 converts into a supercritical fluid state and your cylinder will no longer have a liquid level to measure. We recommend testing CO2 in lower temperatures. Please, get in touch if you need recommendations for hot climate CO2 monitoring.
Yes, however, these agents are far more stable at higher temperatures that CO2, and although the liquid level will naturally rise with increased temperature it is far less than with CO2 and, therefore, can still be tested.
Yes, this unit is specifically designed to work despite the presence of a siphon tube.

Related Products

The Portasteele® CALCULATOR is the perfect partner to any of Coltraco Ultrasonics’ liquid level detectors. It allows you to convert your measured liquid level to an agent weight, precisely and accurately. These readings can then be saved and exported for future reference and traceability. 

Used in partnership with the Portalevel® Ultrasonic Level Indicator range 

P/N: CALC-007

Portalevel® MAX MARINE PLUS is a highly capable, handheld liquid level indicator with ABS Type Approval for marine applications in level monitoring. Portalevel® MAX MARINE PLUS is fast, accurate, and reliable; with a survivable construction and cutting-edge ultrasonic capabilities, it allows an operator to non-invasively monitor the liquid level of almost any CO2, Halon, or Clean Agent fire suppression system at sea.

P/N: 2290334-COMXPSM
NSN: 6680-99-192-2735
IMPA MSG P/N: 652776