"water test" for residential heat exchangers - thoughts?

I'm curious on opinions from pro's of the water test for residential heat exchangers advocated by Ellis Prach of http://www.heatexchangerexperts.com/ In this test, the tech pulls the blower, douses the exchanger with a water solution from a large sprayer, and then looks inside the combustion area for water penetration. If there's water getting in, they reason, you have a breached heat exchanger that they recommend replacing it.
I'm suspicious of this Prach guy though... a self-proclaimed heat exchanger expert, and evidently pontificates--in his seminars he holds all over the country training HVAC techs--that he can even find leaks in a heat exchanger that's 3 years old. His seminars are apparently quite hands-on and he travels with several actual heat exchangers and demonstrates trouble spots on each. I've talked to two attendees and they concur on these points.
So, do y'all think this is a worthwhile diagnostic test that correlates with real safety issues, or just a great way to sell new furnaces and make this Prach guy rich giving seminars from companies so willing to have him teach techs to find leaks in 3 year old heat exchangers?
The whole thing seems to hinge on the assumption that if the heat exchanger isn't water tight, then it isn't air tight, and the further assumption that pressures inside the furnace are such that combusion byproducts might actually make it into the airflow of such leakage areas.
My own situation that motivates the question: a tech (from a significant, well-respected company in Chicagoland that I've used for years because they invest in training their techs rather well) had attended a seminar by this man recently, and had come to give my 15 year old Carrier furnace the annual cleaning and once over. Perhaps it was the age of the furnace, or the rust on it from the prior owner not occupying hte house for the prior two years, but soething compelled him to drop the blower and perform this new test he'd learned recently. Now, this is a furnace that had a visual inspection and tested CO free on all chambers last November for whatever that's worth. I understand that for CO to form and get into ducts you need a lot more than an HX breach.
Personally, I may go ahead and replace the furnace based on age and the suspicion alone, and enjoy the comfort and efficiency afforded by a newer 2-stage and/or variable speed furnace since my time horizons in this home are long enough to get the payback.
But I remain curious what folks think about this test all the same, and the likelihood that my current furnace _really_ has a safety concern.
Thanks in advance for any constructive thoughts or discussion.
Best Regards, -- Todd H. http://www.toddh.net /
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On 13 Sep 2006 23:53:38 -0500, snipped-for-privacy@toddh.net (Todd H.) wrote:

Seems you've already made up your mind but I'll give you my .03 worth. I previously worked for a national hvac company that adopted this practice like it came from the bible. This company was also into high pressure sales practices and tactics. One little twist they added to the test was to make sure the heat exchanger was nice and hot right before they started spraying water on the heat exchanger. Common sense tells you that hot thin metal and cold water are not a good combination for a homeowners heat exchanger. CO tests, detectors and visual inspections and cameras are a more advanced way of checking heat exchangers. Bubba
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Thankfully this company didn't do that! Since it's still a bit A/C season, he didn't want to run the furnace to put the HX through that thermal stress, but he did clean the burners and everything and then was curious enough to do the inspection. It was done with a room temp HX. He did a visual with mirror but I don't think I saw a camera involved.
Tis interesting though how many different ways there seem to be to check HX's.
-- Todd H. http://www.toddh.net /
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1) I thought combustion chambers were supposed to run dry. Isn't adding a bunch of water a rust hazzard? 2) if you're getting zero monoxide, why are you continuing to test? Trying to find a reason to think there is a leak? 3) The quote on the manual page that "most of the furnaces had a crack" only means to me that he's found an indicator that shows positive on everyone's furnace 4) solution, eh? Some kind of detergent stuff that really soaks through? Doesn't mean that flue gasses go the other way.
I'm not going to waste a lot of time on this "new" technique.
--

Christopher A. Young
You can\'t shout down a troll.
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On Thu, 14 Sep 2006 12:05:25 GMT, "Stormin Mormon"
It's a valid technique you knob. Will you waste time fighting the lawsuit that is sure to follow when your incompetent ass kills someone? Your stupidity never ceases to amaze!
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On what basis do you say this Al? One of the reasons for my original post is to find out whether a study actually been done correlating this technique's results to actual combustion chamber -> duct gas flow, or is it all based on the assumption that if a water solution can get in then surely gases will go the other way.
I'm guessing no one would fund such a study aside from a consumer advocacy group. The manufacturers certainly wouldn't want to undermine such a wonderful test where the customer can be shown water on their heat exchanger, and be made to think they're going to kill their family if they don't replace it.
-- Todd H. http://www.toddh.net /
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On 14 Sep 2006 11:27:18 -0500, snipped-for-privacy@toddh.net (Todd H.) wrote:

On the basis that I do this stuff for a living. If there is a crack in the hx and you pour water over it while observing the inside of the chamber you will see the water. Now whether the crack will let co in the airstream is another question. You can have a large crack and not let any co into the supply air stream, it all depends on whether the system has positive or negative air pressure in relation to the hx and supply airstream, which depends on a lot of different things. That still does not mean it is safe to run the damn thing. It also depends on what state you are in. Some municipality's require the heat and ac company to disable any heat system with a cracked hx and inform the utility of same.
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(Todd H.) wrote:

Oh yeah? You need to talk to my plumber.
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Oscar_Lives posted for all of us...

That's methane.
--
Tekkie "There\'s no such thing as a tool I don\'t need."

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wrote:

Give him this.
http://www.jengajam.com/r/crack-spackle-crack
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But what if the water is coming in at the clamshell joint that's a manufacturing reality in many HX's and there is no visible crack, other than the joint itself, which of course is there by design?
What I'm hinting at is this is a test that smells like it may have a fairly significant false positive rate and no one seems to have any data on it.
Best Regards, -- Todd H. http://www.toddh.net /
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On 14 Sep 2006 22:58:34 -0500, snipped-for-privacy@toddh.net (Todd H.) wrote:

If water is coming through, clamshell or not, it's got a crack or it's manufactured wrong/faulty, period.
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On Thu, 14 Sep 2006 12:05:25 GMT, "Stormin Mormon"

Stormy, Once again you prove your complete lack of knowledge in the hvac industry. Here is one for you to suck on for a while. You do know that you can have a heat exchanger with a hole in it big enough to put both of your fists through and still not register any CO reading, dont you? Of course not, I didnt think so. So would you let that customer continue to run their fossil fuel appliance with that large of a hole in it that wasl correctly registering a "0" CO reading? You REALLY shouldnt be allowed anywhere near a customers appliances. You are scary and dangerous. Bubba

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Could be fine. Maybe, maybe not.
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Yeah, that's what I suspect too. This test is a dealer's wet (literally) dream, but I suspect has a false positive rate that is alarmingly high.
-- Todd H. http://www.toddh.net /
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Todd H. wrote:

Pour a bucket of water over your open gas kitchen range and into your oven. I guess if a drop of water makes it under the burners, that should be thrown out too.
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snipped-for-privacy@toddh.net (Todd H.) wrote in

New exchangers from the factory aren't water tight. It has become increasingly difficult to ascertain whether or not a heat exchanger has been compromised due to rust or cracks. Newer exchangers are multi-pass, which makes visual inspections very limited. There can be other tell-tale signs of a faulty exchanger, such as popped rings on top of the blower housing, but again, very dificult to see unless you have a boroscope. A tripped limit or burner spill switch may also indicate a crack,hole, or separation. Flame distortion with the blower on, flame roll-out, continuous pilot outages caused by air from the fan blowing through a crack. (Always a good idea to operate the fan with the burners off and watch the pilot for distortion. I got fooled once as a rookie by a cracked heat exchanger. I replaced the t/couple on an older furnace thinking it was just old and tired. It blew out after I left and another tech picked up on it with the fan-on test.) The best advice I can give for homeowners is to have your furnace cleaned once a year, and have a CO detector on every level where people sleep. Replace it before it's old enough to vote.
--
Respectfully, Bob

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snipped-for-privacy@toddh.net (Todd H.) wrote in

This technique wouldn't do much for all the insulation that is attached to inside of the furnace compartment....
--
Respectfully, Bob

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