Combustion Readings. this months column PHCP Pros

This article contains some good information such as how often test. When contracters say they just at the beginning of the heating season I wonder how they get to every customer that day. Of course there are indirect waters heaters and water heaters that run all year long.

Testing in the proper location is important. Above drafthoods and barometrics is useless information. But where in the drafthood do you measure? If you have a mushroom or round drafthood you locate you probe where the lowest O2 reading of the highest CO reading. The highest flue temperature is the wrong place. If you have a built in rectangular drafthood you have to test each and every burner. On the same piece of equipment with multiple burners I have found one burner underfired, one burner misaligned and several burners not venting properly, When I hear techs tell me they have never seen this I immediately know they are testing incorrectly.

Checking gas pressure first? The burner has to be running to do this and don't we want to know if it is safe? If you understand combustion readings, the combustion tests tell us if we have enough gas or not.

If draft is not proper we are standing in a deadly environment. I thinking living during the testing is more important!

CO Air free is calculated from the O2 reading and the CO as measured. Because the O2 sensor responds faster than the CO sensor you can get all kinds of radical readings. I have had situations where experts?? stated the Air Free CO was the greatest after the burners shutdown. In reality the O2 reading rose faster than the CO. I guess if you want to be sneaky you can scare the customer with that reading. Do CO Alarms measure Air Free? If you don't have an O2 tester or your O2 is bad can you still test with confidence? Yes!Yes!

Can the flue temperature of a condensing boiler be below 140 degrees if it is producing 160 degree hot water? This one I don't have enough experience to comment.

Efficiency. This is the subject manufacturers of combustion analyzer ask me to skip. That was the first discrepancy I discovered in the early 1980's. As I sold combustion analyzers and helped my customers on their initial tune-ups, we noticed that the efficiency on the analyzer didn't go up and sometimes went down and they were saving thousands of dollars. My early customers were most commercial. The efficiency calculation on most/all combustion analyzers is off anywhere from 10% to over 50%. I have shown in class how I can adjust equipment poorly and the analyzer calculates the efficiency at over 90% and the actual meausured efficiency is less 50%.

One additional note, no one that has used a combustion analyzer properly has ever had to go to court.

Good info from From manufacturers rep RL Deppmann blog.

Dirty, plugged mod con HXers are when you may start seeing yellowed, over-heated PVC vent pipe.

@captainco , that might be due to the fact that a lot of installers only measure the gas pressure to the burners when setting up a boiler- if they check anything at all. Like yours, my analyzer has caught a LOT of out-of-tune gas burners.

You're preaching to the choir here.

From a liability standpoint, if you do not test at initial commissioning, you have installed a potentially hazardous appliance into a structure without verifying proper operation and safeguards are in place and functioning as designed. That transfers liability from the mfr. to YOU. If you provide a service and cannot prove the equipment was operating per the mfr. without unreasonable hazard to the public, you are liable. If you test but fail to communicate the results or their bearing on the suitability for continued operation, it constitutes a failure to warn of any existing or potential threats. In other words, you can test and tell the owner "it's ok and firing great" then leave. That does not convey the duty of care the owner has to anyone who would have cause to enter the property, whether resident or visitor, whether code official or first responders or service providers for a place reasonably free from risk of undue hazards.

The equipment cannot reliably achieve its stated efficiency and performance specs. unless installed and operating PMI. The only way to know that is to test.

Even in multiple poisonings they don't always check. This happened in Ocean City, MD back in 2006. An improperly installed mod-con boiler in the Days Inn filled the boiler room with CO and it got in some of the rooms. Some guests were taken to the local hospital and it took them a while to figure out what was happening. And the town inspector had passed the job, even though it did not conform to the I&O manual. At least one person died as a result.

I don't stay at that Days Inn.

I had two furnaces installed in two homes. Neither company used a manometer or a combustion analyser. I figured they trust the that the furnaces were preset at the factory. They didn't even clock the meters. I didnt feel like asking about it.

The fire depts. only report possible CO when they rescue someone from smoke or a bystander suggests a CO incident. I've experienced this many, many times as both a paramedic and volunteer fire fighter. The index for suspicion as it is called is very low. You almost have to feed it to them to get a CO exposure into the national fire stats. EMS is much more aware and, in general do a commendable job at suspecting and reporting CO so the ER doc runs an ABG(arterial blood gas) with COHb to get it into the records. Still, the incident is not going to get picked up by national reporting unless the carboxyhemoglobin is 10% or higher.

I have a problem with publishing signs and symptoms of CO poisoning. You see, in my experience, s/s are always a very late sign/ symptom only once you have met the medical definition of CO poisoning in a smoker- that magic 10%. As for that dopey 'cherry red skin color', I saw it on a dude who backed his 60's hot rod up to his mobile home, ran a rubber vac. hose from the tailpipe through the bedroom window, cranked it up idling, ran in, shot a can of high expansion foam across the bottom of the door and laid down. I saw it some a few in the 15% club that survived but only after a ride in the HyperBaric Oxygen (HBO) chamber. You run them at 3 ATA(atmospheres absolute) so their PaO2 exceeds 2000( normal arterial O2 might hang around 75-100. At that super elevated PaO2, the partial pressure forces the CO off the hemoglobin molecule where it is blown off as we say in the lungs. I'd prefer to focus on the circumstances of possible exposure and just get your butt tested rather than wait on symptoms. A lot of damage is being done to your cells while you wait to hit the mark then home you stay awake long enough to get to the ED( can't do the test at your neighborhood Doc-in-the-box).

My own company forgot to bring the CA for a modcon LP furnace installation. The PVC off the vent collar discolored over night. I was sent with the tech the next day. I immediately opened the cabinet and read the rating plate: 100 MBH of natural gas. I confirmed it was being fed LPG. I pulled the orifices, photographed and gauged them. We were firing that pig at 2.4 times the rated input rate. We had to replace the unit. If the tech had run CA before he left, he would have picked up on the grossly out of whack readings and noted the thing shutting off on high limit. He had also forgotten to reduce the fan speed to the proper setting, whch hid the delta T, stack and plenum temp disparities. We recently bought 5 new UEI's so we'll see how they do.

Side note: do you print out a copy of the analysis you run with time and date stamp? Do you print one for your office records? Note this is a legal record. Leaving it there establishes it was left operating properly, shows any tech who follows how he needs to leave it, and demonstrates professional service not only to the customer but to any litigant.

I can't believe after that study in Rhode Is. where one small community hospital screened 100% of all patients who entered the ER for any reason, including if they fell ill while visiting, slipped and fell on hospital property or walked in. They used that Masimo RAD57 pulse CO oximetry meter and recorded every SpCO. They discovered a significant number of people who had no clue they were suffering from CO poisoning and there was no clue or suspicion communicated to the ER staff. In other words, they would have missed it.

Since CO blocks delivery of O2 to every cell in the body, the damage resembles that of drowning or suffocating. Cells starved of CO die off- period. Are you willing to huff enough CO until you get symptomatic to test or get treated? How many times are you willing to go through some level of suffocation? Daily? Every firing cycle? Nobody tracks, much less talks about CO morbidity. Chronic low level CO morbidity will remain in the shadows for the foreseeable future. I even tried to get my old medical control MD interested. I see there are a number of anesthesiologists and HBO operators involved, esp. several at Children's Hospital of Phila. (CHOP), Univ. of Penn( next door to CHOP), and around the country. Maybe I'll make this my life's work in my latter years.