Are you getting an accurate reading from your CO analyser?

14 May 2013

                              ESV is reminding gasfitters to ensure they use carbon monoxide detection equipment in accordance with the manufacturer's instructions to ensure an accurate reading. ESV has recently investigated a number of reported cases of carbon monoxide (CO) spillage from gas heaters, only to find that the CO detection equipment being used displayed false readings because of the way it was being used. This is because the CO detectors were being exposed to temperatures greater than their maximum rated value because the gasfitters were not taking into consideration the limitations of the equipment. ESV's Technical Information Sheet 37, Carbon Monoxide Measuring Equipment, says:

"Do not place your CO detector in front of a heater's discharge air stream as this hot air may overheat the CO detector and cause false CO readings. You should know the maximum rated temperature of your CO detector before positioning it in an environment subject to heat. If in doubt please contact the equipment supplier."

It is important that gasfitters read the instructions that are provided with their CO detection equipment and take note of its temperature limitations. Many CO detectors have a maximum rated temperature of 40C to 50C. Placing these instruments in front of the discharge air stream of a space heater or central heating duct air supply register could result in false CO readings. These instruments are designed to measure ambient air quality within the room and are not designed to measure CO in a heater's discharge air stream. If you need to check for CO in a heater's discharge air stream you must ensure the instrument is able to cope with the temperature of that air. Exposing the instrument to too much heat can damage the instrument, including the electrochemical sensor that detects carbon monoxide. If in doubt, contact the supplier of your equipment. Alternatively, use an instrument with a sampling probe (pictured above right) so that measurements in the discharge air can be taken using the probe so the testing instrument is not subject to high temperatures. A typical example of a CO monitor that should not be placed in the discharge air stream of a space heater or central heating duct air supply register is the TPI 770 carbon monoxide gas detector (pictured above). This instrument has a maximum rated temperature of 40C and is suitable for use in ambient air only, not hot heater discharge. For further information, call the Gas Technical Inquiries line on 1800 652 563.