Combustion Analyzer Issue

slevinkalevera

Dear All,

I have been having a problem for the past few weeks on my combustion analyzer. I have a LAND's LANCOM III combustion analyzer.

The issue is that
1. the response time for the combustion analyzer after its probe is inserted into the flue gas draft is extremely slow. From slow I mean that from normal 21% O2 it takes almost 10 minutes to come down to 5-5.5% O2 and settle down on one reading.

2.Moreover I am quite sure that the flue gases don't have much excess O2 in them from the color or the flame and the black smoke in the exhaust stack(Heavy Fuel Oil). However the analyzer still shows 5-6 % excess O2.

3.Also when I give the combustion analyzer a power and a purge cycle, on the same point on the combustion curve it settles at a different excess O2 value. For example if last time it settled on 4.89% the next time it would settle somewhere around 5.6%. Every time this value changes.

I have checked the gas and air modulation motors or the dampers plus other instrumentation. All seems to be fine with stable control.

Does anyone have any idea as to what could be the cause of the problem. I recently got my combustion analyzer serviced. However the dessicants and filters are not brand new.

Thanks,
SMA

DuMass

I’m not familiar with the LANCOM III, but generally with most combustion analyzers, one thing that will contaminate and quickly ruin the O2 sensor is using the analyzer on an oil system with a high smoke number, greater than # 2, which sounds like it may have possibly happened because you mentioned "the color of the flame and black smoke in the exhaust stack".

I would probably have the sensor replaced again and the unit recalibrated. Maybe change the filter at the same time as well, just to be sure everything is up to spec.

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phbsales

I agree with DuMass. Get the sensors replaced. Also, make sure there isn't any moisture trapped anywhere in the lines after you use it. That'll chew up sensors as well

I'm using a TSI 6100 series analyzer. The replacement sensors come pre calibrated. Everything is plug & play.