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Combustion analyzer


fyrmnk
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Hi all, I posted this in the "Tools and Equipment" section as well, but thought I'd give it a shot here also.

Since I like toys and all, I was considering buying a combustion analyzer. I was looking at the Bacharach Fyrite Tech 60. I like that it also measures CO, so I could kill two birds with one stone.

Has anyone had any experience with combustion analyzers? Do they do a good job of indicating heat exchanger holes since most heat exchangers aren't accessible to view? Thanks for all input.

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Kevin,

If you like toys, go for it. The practical use will depend on the type of heating you are checking and just how far you want to go.

The purpose for analyzing combustion from the HVAC tech's point of view is to fine tune the burn, especially from an oil burner. A lot of factors come into play here. One of those factors is the atmospheric conditions at that moment. What may read fine to you today may well be off tomorrow or vise versa. So you need to be careful here.

If you really want to check a heat exchanger for leaks, use sulfur sticks.

George

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Originally posted by a46geo

If you really want to check a heat exchanger for leaks, use sulfur sticks.

George

Ye-e-e-s? They the same as smoke tablets? Hmm?

And I agree with George about uses - but would add that I can't imagine any use for a HI. Doing combustion analysis is beyond the scope of beyond the scope.

-David

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Way beyond the scope. I've used this only on setting up gun burners on boilers. I'd be very careful about verifying the integrity of heat exchangers.

Closed System - Unable to inspect, The heat exchanger portion of a gas or oil fired heater is difficult to access without disassembly, and cannot be adequately checked during a visual inspection. We recommend a service contract be placed on the unit and a licensed HVAC contractor called to verify the condition of the heat exchanger.

One way we use to check heat exchangers - spray a salt solution into the burner/heat exchanger, check at the diffusers with a halide torch. Another method was a smoke bomb (for those with big brass one's.)

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True story.

I just graduated from a local HVAC tech school back in the late 70's (complete with leisure suit, ok, the leisure suit was made up but helps in setting the tone).

I went over my brothers house and offered to check his counter-flow furnace for "proper operation".

I set off a smoke bomb, in the furnace, to check the heat exchanger. After my brother, his wife and 3 kids and I evacuated the home for about 15 minutes, we returned to find the house was still very smokey, the parakeet and hamster had passed away but much to our gratification the smoke detectors were announcing an emergency. His wife had no sense of humor about the whole experience but my brother and I had quite a few good laughs reminiscing, over a few cold ones, from time to time.

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Sulfer sticks work best on ribbon burners. Use a smoke bomb for a pot or fountain burner. The sticks will work on in-shot burners, but sometimes are harder to light. I wouldn't bother to open a sealed combustion chamber.

Try this; Next time you actually see a cracked or rusted through heat exchanger, toss in a sulfer stick or smoke bomb. Chances are you will get nothing into the living space. Very few cracked heat exchangers actually leak fumes into the house.

REALLY ... The only way to know if there is or is not a breach of the heat exchanger is to take it apart and visually inspect every inch of the it. Anything short of that is inconclusive.

Our best bet is to use a good quality CO detector to test for anything in the air distribution and disclaim heat exchangers along with an explanation.

George

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Kevin -

As a graduate of a year long Vo-Tech program in HVAC back in the early 70's, a ME Degree with a major in HVAC, and a past Factory Rep for a Major Manufacturer of HVAC equipment let me throw out a few facts regarding checking for holes or cracks in a HE, or checking a HE for carbon monoxide.

If you can see a hole or a crack - terrific.

If not, like George said - there are several methods to use that may lead you to believe there is PROBABLY a defect in the HE - BUT the ONLY totally SURE way is to TAKE IT APART.

We have set up units in the factory where we put varied size holes or cracks in the HE's and then run and monitored them for CO for weeks.

Under certain conditions and with the proper temperature, humidity, pressure, etc. they did not leak CO - even with golf ball sized holes.

Bottom Line - If the unit is very old, very rusty, has excess rust flakes on the burn chamber walls or on the burners themselves, has any kind of funky flame patterns (heavy yellow flames, flame roll-out, flame lift-off or flames going in different directions, etc) recommend that your client "Have a compentent and Licensed Heating Contractor Evaluate the specified conditions, verify the full integrity of the HE, and then repair or replace as needed".

You probably already know this but, in our area you'll run into Vampires at the HyVee at Noon more often than you'll run into an oil furnace or boiler. I've seen 2 since I moved back to KC in 1989. When I mentioned that at a local ASHI meeting (with about 45 guys present) nobody else had ever seen one other than in books.

Dan Bowers, CRI

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PS for Kevin -

Many of the things I mentioned as a trigger to recommend an experts evaluation of the furnace in my previous post, could be caused by other conditions than just defects in the HE. But, they would all be things I would use to get my client more of an in-depth evaluation of the HE than what you or I can do in a Visual HI.

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Originally posted by a46geo

Our best bet is to use a good quality CO detector to test for anything in the air distribution and disclaim heat exchangers along with an explanation.

George

With gas units I check the supply plenum with a CO detector with a MonoxerII with a probe.(Usually on the QT.) If there's CO in that short space between ignition and blower, then I document it. If there's no CO, then I don't report that I've even done the test, but just use the standard HE disclaimer. Works for me.

With oil, I tape the inspection port cover open with foil tape, and hold my hand a comfortable few inches away from the open port. If I get a blast of hot air when the blower comes on (blower pushing duct air into the chamber), I report a HE breach.

-David Lee in VA

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