KM330 Industrial Thermometer (Type K)

Part No: KM330 (3078073)

The KM330 Industrial Thermometer is a Type K thermocouple thermometer for checking temperatures in industrial applications such as heating, ventilating, air conditioning and refrigeration.

  • Temperature Range: -58°F to +1999°F / -50°C to +1300°C
  • Protective Slip-on Boot with Desk Stand
  • Sub-Miniature Connector
  • Warranty: 1 Year

KM330 Industrial Thermometer

The KM330 Industrial Thermometer is a value for money, electronic Type K thermocouple thermometer for checking temperatures in industrial applications plus those in heating, ventilating, air conditioning and refrigeration.

  • Selectable 0.1°/1° resolution
  • Displays temperature in °C or °F
  • Maximum temperature memory
  • Hold function to freeze displayed reading
  • Protective slip-on boot with desk stand
  • Sub-miniature connector

The hand-held KM330 Industrial Thermometer is easy to use, with proven type K thermocouple technology and a wide range of optional probes and sensors.

The KM330 Thermometer is a single input thermometer with a wide range of applications. Users can select readings in °C of °F and high or standard resolution to suit their requirements. Hold and Max functions are provided, to freeze the last reading on the display and to record the maximum value.


Technical Specifications

Temperature Measurement Range-50°C to +1300°C / -58°F to +1999°F
Scales°C and °F
Resolution0.1°C or 0.1°F
Selectable 0.1/1° Resolution0.1 only up to 199.9°C
Accuracy @ 23°C (73°F)
+2, -1°C-50°C to 0°C
+4, -2°F-58°F to +32°F
±0.2% rdg + 1°C0°C to 1100°C
±0.2, -0.7% rdg ±1°C+1100°C to +1300°C
±0.2% rdg +2°F+32°F to 1999°F
Temperature coefficient including Cold Junction±0.01% rdg ±0.04°C per °C change from +23°C
Update Rate2.5 times per second
Ambient Operating Range0°C to 50°C / 32°F to 122°F
BatteryStandard 9V PP3 battery (NEDA 1604, IEC 6F22)
Battery Life200 hours typical with ALKALINE battery
Dimensions (Instrument)174xx(H) x 70mm(W) x 39mm(D)
WeightInstrument 210g / 7.4oz, Protective Boot 133g / 4.7oz
Warranty1 Year

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Articles / FAQs

Why is my KM330/340 displaying ‘OL’?

Why is my KM330/340 displaying ‘OL’?

If you own a KM330 Industrial Thermometer, or a KM340 Industrial Thermometer with twin inputs, and it is displaying ‘OL’ on the LCD Screen, as shown below, this could be for a couple of reasons.



The ‘OL’ message will appear if your KM330/KM340 Industrial Thermometer is turned on without a Probe connected via the device’s sub-miniature connection.

If a suitable probe has been connected via the sub-miniature connection on the front of the device and the ‘OL’ error is still being displayed, then this can indicate a fault with the connected probe.

In this instance we would recommend that the probe in question is disconnected from the device and a new or alternate probe is connected instead.

Should the ‘OL’ error message persist, despite alternate probes being connected and tried, then the Thermometer(s) in question will need to be returned to our Service Department for repair.

Please click here to visit our page for instructions on returning items for repair.

10th March 2014
My Device is showing unrealistic temperature readings

My Device is showing unrealistic temperature readings

If you have set up your Device correctly, inserted a Sub-Miniature Connector Probe into your Device and taken a temperature reading, only to discover that the temperature recorded is vastly different to that which was expected, then it may be that the Probe Connector was in fact inserted incorrectly.

The Sub-Miniature Connector on all Comark Probes has two prongs, one slightly larger than the other. These prongs are also marked as positive (+) and negative (-) on the cable head itself, as shown below.


The prongs correspond to two similarly shaped slots on the Device, one slightly larger than the other.

In some cases, it may be possible to force the prongs of the Sub-Miniature Cable Connector in the wrong way around. If this is done then the symptoms would be as described above, recorded temperatures that are vastly different to those which were expected.


To resolve such an issue, simply unplug the Sub-Miniature Cable Connector, check the prong orientation and then re-insert.

  • Small Slot = Positive
  • Large Slot = Negative


4th June 2015
My device has corrosion in the battery compartment

My device has corrosion in the battery compartment

This may cause your device to cease functioning, or become dangerous. In all cases, please return your instrument to Comark for servicing.


Ideally, prevention is better than cure for this problem. Check your batteries regularly to ensure they have not leaked, and if you are planning to store the instrument without use for a prolonged period, please consider removing the batteries and storing them separately.

16th April 2015