Utica Boiler Problem

Unknown

For those who are interested installing the new LP dedicated burner solved the problem no more flashback. The burner sent had an air shutter but I have left it open full.

I have gone back and made some fine tuning adjustments, We have good steady microamp readings on the Honeywell S8600 Module system 5 microamps with no fluctuation.

My combustion analysis is:

CO2 7.9%

O2 9.4%

Net Stack after the power venter 310 degrees

Draft -.035

CO air free 35 PPM

Combustion efficiency 85.4%

Dale

CO as measured

Timmie, what was your as measured CO before the free air calculation? Thanks for getting back to us on this, did you see a difference in the LP design burner in the size of the venturi throat?

jim sokolovic

2 good 2 b true...

Sorry, Timmie - your efficiency calculation seems way off. But that wasn't the original problem on the job you're referring to, right?

Unknown

Dale, I do not

remember I did not write it down. The burners were identical in shape and size all that was different was the number of slots in the LP burner was less I assume for better port loading.

Unknown

Jim, those are the

readings that were given of the combustion tester to me I just wrote them down. I have not bothered to plot them out what do you find too good to be true? Is it the high efficiency reading?

jim sokolovic

Just thought you'd like to know...

maybe something is not programmed right on your analyzer. I would come out with a steady-state efficiency of about 82 % with those numbers. Is the flue temperature a net or a gross? Is the right gas type entered (the Oxygen/CO2 conversion is about right)? I have a unit that gives a very high ambient temperature (internal heat is built up by the built-in sensor), so it's useless for the efficiency calculation to me. Good original post and follow-up, though - I always pay alot of attention to the combustion stuff, here!

jim sokolovic

Dale, the uncorrected CO value...

should have been around 20 ppm. Each gas has it's own "ultimate" value - If you use an "ultimate" CO2 value of 14 % for propane (I've seen varying values published):

14 % divided by the measured value of 7.9 % = 1.77 factor

35 ppm air free divided by the 1.77 = 20 ppm CO uncorrected

Hope that's what you are looking for!

Unknown

Jim I checked it after your post and I agree it is

around 82 to 83%. I find that sometimes when you are testing with a combustion air blower the readings get a little funny. I have tried moving away from the blower to test or closer and it seems to make a difference in the readings. I used two different testers on this as I had a new Testo and wanted to see how it matched up with my Bachrach. They were both pretty close to one another but I did not record the TESTO readings. My Bacharach is due for calibration so that may also be part of the error.

jim sokolovic

Some combustion blowers...

add dilution air around the shaft or housing. The downstream readings of CO2, CO, and temperature can be all slightly lower. I wouldn't suppose the readings should change much as you move further down the vent pipe, unless there are leaks at the seams or condensate drain. Taking the readings in the flue collector area (before the blower) will give varying values, and you have to do a bit of work to access this area. I've seen CO2 usually vary by less than 10 % in the collector, but the CO can vary by a factor of 5x (500 % ?)!!!!! I don't think any combustion analyzers are capable of averaging all these readings in the collector if you wanted to take a sampling of the entire inside area - you would have to do the recording (say, 10 places or so) and averaging by hand? Not what you want to bother with in the field, I wouldn't think.

Unknown

Jim I find

combustion blower type equipment somewhat difficult to access for accurate readings. It would be a great help if furnace and boiler manufacturers made a dedicated place for testing which is easily accessible and safe.

I guess the deal is that installers and service techs have not done much testing in the past on gas equipment. As it becomes apparent that in order to solve some of the seemingly unsolvable problems of the past testing is required it will become a necessary addition to the equipment.

I am asked all the time why no place to take the test or how do I take the test on this or that designed piece of equipment.

I just had class the other day and we spend considerable time showing possible test points on all kinds of design gas equipment. You are right however as it is very difficult to get an accurate analysis. The other problem is it takes up a lot of time to do averaging and most techs do not have that kind of time to spend on the job. We do our best to make it safe and as efficient as we can.