Causes of CO

rudy_2

Hi Antman, post the rest of the readings (O2 and draft) and I'll bet we can figure out what's going on.

Just to let you (and any other Bacharach customers) know, please feel free to give me a call if you have CO or combustion related issues - it's the favorite part of my job!!

I'm not the 'sharpest tool in the shed', but I have alot of testing and troubleshooting experience. Between myself and the other 4 guys that do what I do, we can probably give you some suggestions.

My office # is (740)594-0033, cell (412)576-1350. I'd look forward to hearing from you.

Rudy

antman

what to look for ?

I purchased my 1st combustion analyzer at the end of last heating season and was wondering if you guys could give me some tips on performing tests. I do mostly natural gas installs and service so i'm not completely sure what i should be looking for when i do my test other than CO readings. should i be looking for anything else and why?

Today i was performing a routine service on a Burnham American steam boiler everything looked fine, burner tubes clean, cast iron clean, etc. CO readings shot up to almost 2000ppm i removed the probe waited a minute reinserted it shot right back up, leveled off at 1150ppm. Tested the water heater next to it was at about 30 ppm. Any tips? leak in sections? not being fired up in the off season? how would i fix this or do i simply replace it.

I'm really interested in using my analyzer properly so i could really use some insight on how to rectify problems once identifying them.

Thanks, Ant

Oh, i did leave the boiler turned off, not really that necessary yet.

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hot_rod

Some great info

can be found here.

http://www.bacharach-training.com/

hot rod

Unknown

Did you take

a CO2, O2, Flue gas temp,draft, excess air, and was the CO reading taken at the breach of the boiler before the draft hood? What was the input to the boiler? Did you clock the burner to see if it is overgassed? Is the flame burning blue or is it yellow? Check your gas pressure to make sure it matches the rating plate setting, usually 3.5" W.C. to 4.0" W.C.

Take the boiler apart and make sure it is not partially plugged.

Make sure you have sufficient air for combustion in the boiler room.

The 30 ppm on the water heater is acceptable.

I have some good literature available to help you with understanding combustion testing.

Mark Hunt

CO


How long did you let the boiler fire and what was the temperature of the system when you took those readings?

On a cold start it is not uncommon to see huge spikes at light off.

How long did you test after you fired it up, and did the readings drop?

Mark H

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Steamhead

Antman, Tim is The Man

when it comes to combustion analysis on gas appliances. If you can't get to one of his seminars, at least start with his Fundamentals manual. It has the best CO section I've seen. Tim will send you a catalog if you e-mail him your address.

For what it's worth, every time I've seen high CO on a gas boiler, it was over-gassed. This causes the flame to burn too high and hit the cast-iron sections, chilling the flame, causing incomplete combustion and CO formation. But check everything Tim mentioned.

We've had reports of gas regulators screwed all the way down in several cities. This misguided practice is going to cause a disaster someday. If you find this on your Burnham-America, CHECK EVERYTHING ON THAT BOILER since the same person may have messed with something else that you won't see unless you look.

You'll find that your analyzer is one of the most useful tools you own. "If you don't test, you don't know".

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antman

testing

When i had arrived the system was off but had been running earlier in the morning.I had the unit running for a about 5 minutes prior to doing my test. I left my probe in the breaching before the draft hood for a good 10 minutes and it kept floating around the 1200-1500 ppm range.
The building is a condo so i could not gain access to gas meters to clock the input, i will definately check that afetr making arrangements with the complex. I did test for CO2, O2, Flue gas temp,draft, excess air, not to sound foolish but i don't know what the readings should be. When i get back there this week i will post the results from my print out and maybe you can shed some light as to what i am supposed to be reading on the meter when testing, and what to look for in the event the readings are coming back improperly

Ant

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Unknown

Antman, some ball park

figures for gas boilers:

CO2 8.5% to 9.5%

O2 4.5% to 6% (no lower than 4%)

CO under 100ppm ( I like to shoot for under 50PPM not always possible)ANSI Standard allows 400 PPM in the flue sample (air free).

Excess air should be around 25% unless you have power assisted then it should be lower.

Flue Gas temp between 350 to 450 degrees F - that is net stack - measured minus room temp - your analyzer should do that for you. Flue gas on gas can not be above 600 degrees F net. Watch out for lower temps which can cause quenching of the flame and make CO.

These tests should be run with all doors closed and every fan in the building running. Make sure the equipment doors are all in place and close the boiler room door.Then check your draft with a gauge or some analyzers give draft it should be -.02, -.03, -.04 I do not like to get above -.04 on residentail burners excessive draft means too much excess air which lowers CO2 and efficiency.