Carbon monoxide testing of the gas appliance, Part 2

[@3beltwesty]

0 ppm is Normal Fresh Air 9ppm is ASHRAE recommended maximum indoor CO level. 10 to 24 ppm is where possible long term health effects might happen. (If you are already ill, or have a bad heart, or are a child then these low levels are risky to you) 25 is what the maximum for 8 hours via a TWA (time weighted average) ACGIH uses. (American Conference of Governmental Industrial Hygienists) 50 ppm is what OSHA uses. EPA uses one hour 35 ppm TWA and 9 ppm for the eight hour TWA.

[@grayfurnaceman]

I have read all these numbers. They are mostly worthless in the field. These numbers do not take into account the health of the person in the structure (as you say). I have known people who would die at 10 ppm. No joke. If you read any CO in the structure (unless there are smokers), start looking for a problem. Forget the numbers published. GFM

[@3beltwesty]

The CO subject is really an interesting area. A medical doctor relative in Seattle office had a gas water heater that ran legally well below the 100 ppm in the exhaust stack; ie 20 to 45. The inside air would read zero when the HVAC guys tested it. BUT my relative still felt slightly ill at times on long days. This only happened a few times a month. What complicated the matter is the relative was a Doctor who believed all sorts of stuff around the home and house makes one feel ill. ie electric meters, cell phones, TV's, computers, plastics. What was happening is there was an odd backdraft on rare times would bring the CO into the building. ie it took a Colombo better HVAC guy to really fix the issue. The landlord actually replaced the gas water heater with a modern one that ran radically cleaner but there was still every blue moon some CO in the working area. My relatives "home type" CO detectors really never detected the CO, often these are just to alert dangerous levels and not minor levels. What was happening is another tenant in the building had this exhaust fan that created some odd airflows that caused the issue. Here I have a Testo 320 for the furnace and a Test 317-2 to measure CO in the inside air.

[@mrofnocnon]

With a high C.O reading in the vent check that it is clear at the termination and check the gas manifold pressure to make sure the firing rate is correct.

[@3beltwesty]

Small amounts of CO to a healthy young person just add all sorts of minor problems, you are weaker, argue more, have slight headaches. ie you do not die you are just "off". This happens in stores with floor polishers, ice rinks etc where the propane engine added a tad of CO.

[@HankeyRoger]

The test method shown in this video is NOT recommended since it does not discuss how the level of CO in the vent changes during operation. A useful test is to measure CO in the vent using a Bacharach Monoxer or similar instrument. These have a pump and a continuous readout. I like the newer Monoxers which have a graphing function. The key is to begin the test BEFORE starting the furnace and watch the CO levels as the burner comes on. Typically, the CO level will rise rapidly until good combustion develops (a few seconds), then drop to the teens or twenties (ppm CO). The most important point is to watch what happens to the CO level when the main BLOWER starts. The CO level in the vent should NOT change. If the level changes (other than continuing a slow decline), there is probably a heat exchanger concern. If the CO level begins to rise when the blower begins to push air around the heat exchanger, this can be an indication that the blower is influencing the combustion. If you instrument has a temperature probe, watch for any change in vent temperature when the blower comes on. A rising level of CO in the vent and/or a cooling of the vent temperature are consistent with the introduction of ambient air into the combustion chamber, cooling the flame and producing carbon monoxide. The CO will be vented out (unless the vent is damaged or loose) and typically NOT enter the air pressure on the outside of the heat exchanger is much greater than the pressure in the combustion chamber (which is actually a negative pressure due to the draft inducer). This is the main reason forced air furnaces are relatively safe even when the heat exchanger is damaged. A cracked heat exchanger lets air into the combustion chamber, not combustion products into the circulating air. Please go to the carbon monoxide safety association website for more detailed information. Please do NOT rely on the test shown on youtube by grayfurnaceman

[@charleslamp6288]

A guy from whaul heating came to my mother's house today a said his test read 400 yet she has not had any signs or symptoms of any level of poisoning not to mention I was there all day Sunday and had no symptoms or sick feeling

[@HighVoltageMadness]

charles lamp cracked heat exchanger furnace scammers

[@cbishop41483]

Wow, never ever ever jump out a safety, they are there for our protection.

[@homeinspectionsofchicago]

Thanks Gary. Great video.

[@grayfurnaceman]

Welcome GFM

[@RockoRocko-rz7kx]

I've seen holes in the heat exchanger so big I can see the back of the furnace cabinet clearly in a standing pilot furnace with draft hood and there was no co found inside the plenum with my bump tested co detector, as the combustion process was burning clean. Carbon monoxide is a by product of incomplete combustion, usually because the combustion process is starved of air or the flue products are not escaping to the outside of the home or heat exchanger is plugged. However gas code states in my area if cracks or holes are found. The heat exchanger shall be replaced.

[@3beltwesty]

Locally the cracked heat exchanger gambit is often a scam to sell new furnaces. OR it is their method to avoid lawsuits and deaths. Since the state here is ground zero for suing folks and jackpot justice I guess being safe is done. Many decades ago in HVAC classes in Mechanical engineering I learned a cracked heat exchanger when the air handler is running forces air INTO the exchanger and NOT into the air ducts. ie we measured positive pressure in lab tests as more positive in the ducts than the exchanger. Thus CO did not go into the air ducts. *** BUT during the first preheat of the gas heater before the blower is on one might get CO into the air ducts if the building had odd air flows and the cracks were huge. ie another machine reversing the air flow and then CO would go through the crack into the duct only before the air handler was on. **Thus my take is a higher but still legal CO level in an exhaust stack often still has no risks, BUT there are acceptions. ie the stack might get clogged by birds or come undone and that say 200ppm of CO might get into the living area. Here I have a test 320 to measure CO in the stack and a testo 317-3 to measure CO in the living area. One of my Furnaces is from 1986 and does have cracks but still is legally OK to run from the CO stack numbers. The CO as measured by the testo 317-3 inside is 0. HVAC guys who poached locals after Katrina quoted me 45k to replace the two furnaces and two 5 ton AC units, ie 4500 bucks per ton. There was so much work that they wanted a big deposit and many months just to get any actual work. Today prices are about 1/2 to 1/3 of that. ie the stormers are gone and prices are back to normal. I actually bought the two testos because I wanted to know if my units are safe via actual real Engineering tests and not just emotional cons scams, tiny cracks or scrapping stuff just because it is X years old. Sadly there are many folks killed due to CO issues and too folks who do not want their units checked since so many get scrapped via CO crack scams.

[@RockoRocko-rz7kx]

Co has a specific gravity of 0.9 which means it's lighter then air

[@3beltwesty]

CO is very slightly lighter than room air but its transport is often via drafts. The molar mass is 28 versus air which is about 28.8. Exiting Furnace roof vents with a high CO level can be pulled into an open window or open attic vent. Yes it is lighter than air, but barely. That is why CO is so dangerous, a poorly running unit can have a bad vent joint in the attic and the CO can be pulled down into the building in another path.

[@hangngoaigiare]

and if you have good venting and draft. those are keys.

[@waynemiles7027]

How about explaining co reading on your meter and co air free, they are two different things. Are you talking about co air free or co and what was your meter displaying. Thanks for video and have a merry xmas.

[@grayfurnaceman]

Merry Christmas It is coming. GFM

[@jimgill5706]

Good video and info as usual. Thanks.

[@grayfurnaceman]

Merry Christmas GFM

[@Chris-uh3cm]

Can you go in depth a little more as what to do if you have a high CO? And what’s the proper number that is too high of CO

[@geojor]

valuable advice , thanks ...

[@HankeyRoger]

Not really. See my recent post

[@mikumiku925]

Super helpful, thank you Sir~~ 😍😍😍

[@grayfurnaceman]

Merry Christmas GFM

[@Jeff-Lawrence]

Could you comment on the pump with to Co unit I believe the fieldpiece CO detector is not designed to be used in the flue, but I could be mistaken Do you think using it with the pump in the flue will harm the sensor from other exhaust elements? What is your experience so far

[@RockoRocko-rz7kx]

Carbon monoxide has a specific gravity of 0.9 Odourless, colourless, tasteless If your lucky you may smell a byproduct called alderhyde Which likely usually means u have carbon monoxide. However this is not always present Thus the 30 dollar co detector is a good idea

[@hangngoaigiare]

need personal CO detector when enter a house, check the draft before by pass the pressure switch. if there's no draft from the inducer what the point of bypass pressure sw?

[@sleepwalker29]

Where does it come from in a home?

[@grayfurnaceman]

Fireplace, water heater, furnace, stove, candles, anything that has a flame. GFM

[@johnc4352]

Carbon monoxide acts like it is heavier than air, which means it goes down not up. The lower you are in a basement the worse it is. Think of it like pouring water into a basement, you might be safe on the stairs going down, but it might be deadly at the bottom and once you pass out and hit the floor you are in big trouble.

[@grayfurnaceman]

It actually has a specific gravity almost the same as air. I will be doing one on this soon. GFM

[@MrLaffertyheating]

John C above freezing it is lighter than air, below freezing it is heavier than air

[@plumb-bob8597]

Co is slightly lighter than air, it doesnt act like anything

[@stevebabiak6997]

Fact Checker - they are mounted that high because that is where people’s noses and mouths are, and that is how air is inhaled via noses and mouths. If density is similar to air, then the CO concentration should be somewhat uniform throughout

[@HighVoltageMadness]

Just burning incenses in a plastic bag produces massive amounts of co over 500 ppm in just 2 minutes.

[@grayfurnaceman]

Candles can also produce CO. GFM

[@averyalexander2303]

I don't doubt that. CO is produced when combustion is occurring without adequate oxygen.

[@HighVoltageMadness]

@@grayfurnaceman yeah i seen that too

[@sleepwalker29]

What if I smoked 7 grams of weed in a motel room in 2 joints. Would the smoke create CO2?

[@averyalexander2303]

@@sleepwalker29 It would create CO and CO2.

[@damarcojackson1005]

Does that hand pump come with the meter?

[@derekddurbin]

Where did you get that tubing and hand pump? I’m getting a Fieldpiece SCM4 tomorrow from Johnstone does it come with that or did you have to buy it extra? Thanks

[@grayfurnaceman]

I think it is an accessory. GFM

[@derekddurbin]

grayfurnaceman can’t find where to buy it I’ve checked amazon and online

[@Zig285]

Silly question, but how do you seal the PVC after making that hole?

[@HighVoltageMadness]

tape

[@akawireguy1197]

Do the typical carbon monoxide/smoke detectors work?

[@HighVoltageMadness]

AKA Wireguy not for testing for co

[@mrofnocnon]

Never, ever, bypass a safety device!

[@bradonrauns]

Does that add-on to your fieldpiece detector have a part number or did you make it?

[@grayfurnaceman]

I don't know the part number, but it is on the Fieldpiece site. GFM

[@bradonrauns]

@@grayfurnaceman thanks bud!

[@honolulu1476]

Could you recommend good CO (Carbon Monoxide) detector. Thanks.

[@jeffb8437]

Alex M testo 317-3

[@usastyle500]

Honolulu 147 What about the Field peace monoxide detector

[@rubenviveros7546]

Where can I get that probe accessory?

[@grayfurnaceman]

Try the Fieldpiece website. GFM

[@usastyle500]

I got 13 ppm it’s only 5 minutes and it’s was rising

[@grayfurnaceman]

Where are you sensing? GFM

[@usastyle500]

At the supply register

[@grayfurnaceman]

@@usastyle500 That is not a high number, but if the air in the structure shows 0 or close to it, I would be concerned. Next, I would sample at the supply plenum. If you get the same or higher number, you need to find out if there is a combustion problem or a crack in the heat exchanger. GFM

[@usastyle500]

grayfurnaceman thanks

[@levit7864]

what does it mean if your furnace is venting close to a 100 ppm?

[@grayfurnaceman]

I am not happy with that high of a reading. It could be dirty burners or possible crack in the heat exchanger. GFM

[@levit7864]

grayfurnaceman what about when a furnace has those pieces of metal that sit inside the heat exchanger close to the burners. i had a senior tech say to pull those out.. ive seen those rust out and cause excessive co

[@grayfurnaceman]

I believe the were for reduction of nitrous oxide. I don't see a problem with removing them. GFM

[@stk1975]

So confusing...

[@rayminthecat]

Gas sucks