combustion analysis

[mattmctree]

how often does a combustion analysis have to be performed? everytime a mechanic touches a furnace or only when suspected poor operation is noticed? should it be checked when cleaning flame sensor etc ? just wondering ehat everyones typical procedure and readings they are getting on a properly fuctioning furnace?

[walker]

I check it on pretty much every furnace I touch.  Unless I'm just changing a filter or humidifier pad then I normally don't

[Admin]

Some manuals will have a startup checklist where you can fill in readings for things like temperature rise, manifold pressure, CO2% and CO PPM.  Some manuals require this be done during the initial startup but most don't.  The person who activates the appliance can complete that section to be deligent.  There are no Codes or TSSA Orders / Advisories that I know of that say you must perform fuel gas analysis.  Testing the CO on a natural draft boiler is the only thing that comes to mind.

If there was ever an incident the more notes you make in a journal or on an invoice the better.

[mattmctree]

where do you guys check the flue gas from? drill a whole in the pipe or install one of those special fittings or just at the exhaust termination:? also what readings are you guys typically getting?

[walker]

Can't drill in to the vent if it's ABS/636, if it's C-Vent I drill a hole.

I install the access fitting on all my installs
For testing on ABS/636 I etiher find a spot on the ventor or usually there is a vent transition you can sneak your probe in to.  If there is no good option inside then I go outside to the termination.

[Admin]

Usually for natural gas appliances the CO2 =11.8%.

The O2 is usually below 21%.

The CO should be low but really depends on the appliance.  Some allow up to 400 PPM in the flue.

[walker]

I've attached the AccuTools Combustion Guide, it should guide you in the right direction, it's put together by Jim Bergmann a very smart man in our industry.

[mattmctree]

awesome. much appreciated