Instrument Maintenance
Irregardless of the particular instrument you are using, there are some things that can be done to extend the life of the sensors and the instrument.
Flue gas condensate is acidic and very corrosive. It can eat holes in metal, imagine what it does to electrochemical sensors, pumps, fittings, etc. These components are designed to be exposed to condensate, just not soaked in it for extended periods of time.
-- Most importantly, keep the instrument above the level of the moisture trap, this will maximize the effectiveness of the trap and keep liquid condensate from being sucked directly into the instrument.
-- Maintain the moisture trap in the hose assembly. When you see condensate droplets or liquid, empty the trap.
-- When equipped with yarn or the cylindrical filters (as seen above), it's a good idea to change it out when damp. Consider having an extra in the case and just exchanging them when one gets wet. Just leave the wet one in the case, it will dry out and can be used the next time.
-- If you have emptied out the moisture trap and are done using the instrument, just leave the trap open in the case to further dry out.
-- It's also a very good idea to purge the instrument before turning it off. Once the probe is removed from the stack, disconnect the hose assembly from the bottom of the instrument and let it run for 10 minutes or so to completely remove any remaining flue gases and dry any condensate from the heads of the sensors.
-- To make removing the fittings a little easier, apply a small amount of Vaseline or waterproof grease to the mating surfaces and 'O' rings. This will also insure an airtight seal and longer 'O' ring life.
When packing it back in the case, make sure the hose assembly is disconnected from the instrument.
Temperatures below freezing will not 'damage' the instrument. However, bringing a cold instrument into a warm, humid environment may cause condensate to form on the circuit boards. This is where damage may potentially occur.
While few (if any) instruments have required service due to exposure to cold temps, common sense suggests it not be regularly exposed to temperatures much below freezing.
If it is left out on a sub zero night, let it warm up slowly to minimize condensation.
Carbon monoxide and draft are the two of the more common areas which do require regular calibration. All manufacturer's of combustion analyzers recommend they be calibrated every six months.
A CO calibration kit is available (about $250) that has enough calibration gas for around 30 calibrations - additional tanks of gas are around $100. The Model 300, Monoxor II and Fyrite Pro can be easily calibrated.
Combustion analyzers go through a 60 second 'warm-up' period when first turned on. This allows the O2 sensor to power up and stabilize.
Do not have the probe in the stack during the warm up period, make sure it is sampling 'clean' air.
Pulling a flue gas sample through the instrument during this period of time will not hurt anything, it will just result in totally meaningless test results.
The O2 sensor circuitry does what is termed an 'auto calibration' during warm up. This means that at the end of the 60 seconds, it assumes what ever level of O2 it is sensing is 20.9% and will display that number. In other words, if flue gases were being pulled through at 6%' the instrument would display 20.9% and start off with a 'false zero'.
Many instruments also do an 'automatic calibration' for the CO sensor as well. This means that if the instrument is turned on in air contaminated with, for example, 25ppm's of carbon monoxide, it will display zero.
One safety feature the Bacharach engineers designed into all of our CO instruments is that if the ambient CO level is above approximately 80 ppm's CO, the instrument will read "CO Sensor Error" at the end of the warm up period. This warns the user that they may be in a hazardous environment. These instruments can still be used for CO source investigation, they just need to be turned on outside, in fresh air.
The newest combustion analyzer (the Fyrite Pro) was designed with the ability to also do what is called a 'manual calibration' during the warm up period. This means that once the warm up period is complete, it will read actual levels. If the ambient air is 25ppm's CO, it will read 25ppm's. Refer to the 'Fyrite Pro Initial Set up section of the 'Online Manual' for detailed set up instructions.
The instrument itself should provide 12 to 15 years of useful service life.
Sensors have various shelf and performance lives. O2 sensors typically last up to two years. Carbon monoxide sensors will generally perform for 5 to 6 years. Bacharach warrantees sensors in a new instrument for the first two years from the purchase date. Replacement sensors are warranted for one year.
We recommend not stocking the O2 sensors because they do have a shelf life.
Keep in mind that as soon as the O2 sensor is removed from the sealed container it comes in, it starts sensing O2 , and is working 7/24/365, whether the instrument is on or not.
To extend the life of the O2 sensor, keep it dry. As mentioned above, keep the moisture trap dry and when done testing, it is a good practice to disconnect the hose and probe assembly, and allow the instrument to post purge for 5 to 10 minutes.
The chemical in the CO sensor reacts with CO and produces an electrical current that in interpreted by the computer and translated into CO ppms.
The more CO the sensor is exposed to, the shorter the life of the sensor.
Two ways to maximize the sensor life:
Generally, either sensor can be replaced by the customer or sent to a service center. Keep in mind that a new CO sensor does require calibration when first installed.