I am not an expert when it comes inspecting heat exchangers, but I am pretty good at detecting a scam. The tech was using a the scare tactic to get you to replace your 10 year old furnace and AC. The scam ended when you stared asking questions about the heat exchanger warranty. This is the reason why you didn't get a call back. Good for you for not getting scammed.

I have included a link about heat exchanger inspection methods. I have never heard of the puff smoke test. I thought cracked heat exchangers were found by visual inspection.

If you are worried about carbon monoxide, then I suggest you install a dector near the furnace. Carbon monoxide is lighter than air. You should place the detector at least 5 feet above the floor.

Here is a link that might be useful: Heat Exchanger Inspection Methods

Thanks for your feedback Mike. And thanks for the link. I found that one yesterday. I'm a visual person. I would really like to find a you-tube video of an inspection.

In reading the document that you linked, CO detection is NOT a good indicator of a cracked heat exchanger. I'm curious, I have an updraft furnace so the CO measurement should be in the plenum above the heat exchanger, right? So, what would measuring the CO near the burners indicate?

Mike - on page 12 of the document you linked it states:

"Using a smoke puffer you can fill the burner chamber with smoke. Then turn the blower on. If the smoke sprays out and away from the burner opening you have a good indication of a leak in the heat exchanger."

The tech did demonstrate this. However, the word "spray" is subject to interpretation. Yes, there was some movement of the smoke coming back from the burner, but how vigorous does that movement have to be to be a "spray". Without the burner on the smoke swirled around. Once it was turned on it swirled faster and came out.

So far I haven't been able to find a video of how this looks like in a normal furnace and how it might look with a crack in the heat exchanger.

In my opinion, there should be no CO gas regardless where it is measured. CO gas measured near the burns could indicate an improper mixture of gas and air resulting in incomplete combustion. You should have a nice looking blue flame. If it is yellow, then you are not getting complete combustion.

I think most techs will rely on visual inspections and CO measurement before determining a furnace is not safe. I am not sure of the reliability of the smoke test. It sounds more like a "smoke and mirrors" test.

"I am not sure of the reliability of the smoke test. It sounds more like a "smoke and mirrors" test."

My thoughts exactly. Besides this document, I have not found reference to a smoke puffer test.

Now a little more background - this same HVAC contractor has done the same thing to at least 2 other homes in our neighborhood. 2 with American Standard units and our York. The tech is an old time guy come back out of retirement and swears this is the right thing. The neighbors opted to have their heat exchangers replaced. Seven weeks and 3 weeks, respectively, and STILL waiting for "parts".

Anyone else want to weigh in?

Heat exchangers can go bad, but in most cases they are under warranty.

That is what happened to us. The tech pointed this out and said the company would get back to us. They did with an estimate of almost $3,000 to replace the entire furnace which was just over ten years old. Luckily I save everything and checked the spec sheet we'd been given when the furnace was installed. I called American Standard and sure enough the part was fully covered under the lifetime warranty.

Long story short, we got the new part for the cost of shipping and labor to install it. $500 and some sure beats almost three thousand dollars. Pays to not just take them at their word.

Forty-eight hours and I still haven't heard back from the original HVAC contractor. They were supposed to give me the price to replace just the warrantied heat exchanger and to discuss the potential relocation of our furnace should we be replacing it. (Spec home w/furnace located in the middle of the basement instead of an easily enclosed area. We have a main floor master so our basement is huge. Lot's of space to locate it)

It is unlikely your are going to get a call back because they have no interest in replacing your heat exchanger. This is the same thing that has happened to your neighbors.

If you press them they may come back with a very high price and say for a few hundred dollars more we can replace the furnace.

"If you press them they may come back with a very high price and say for a few hundred dollars more we can replace the furnace."

This is exactly what they did when they first said the heat exchanger was cracked. $2.8-3k to replace the heat exchanger since he claimed the 10 year warranty was expired (not - has a lifetime warranty) vs $3.2k for a new Everrest system. BTW...has anyone seen some of the marketing stuff from Everrest on the web? Seems rather high pressure to sell....selll....SELL!

workingmom,

I inspect furnaces on a daily basis. I would be shocked if there was anything wrong with your heat exchanger. The only real test is a visual inspection. It sometimes involves pulling the blower motor and a mirror. If you still don't feel safe ask another heating contractor for a second opinion. Most good companies will offer 2nd opinion calls for free. maybe then you can find a good company to start doing your semi-annual maintenance.

I couldn't get the second opinion for free, but I do think I found a reputable company to work with. They distribute York furnaces, which is what I have. I've gotten good feedback from a number of friends and acquaintances, so I'm sticking with them from now on.

I suggest that you call your local Gas utility that supplies you with natural gas and ask to have a tech come out to inspect your furnace. Just tell them that you smell gas when you get around the furnace. They will be there and take a look immediately.
My DH worked for So Cal Gas Co for 43 years and I was a General Contractor for over 25 years. Between the 2 of us we know about gas appliances.

Thanks anitamacey. I didn't think about calling the gas company. I'll check into it.

...i'm so glad i found this forum. i had this exact thing happen to me yesterday. heating guy comes out and starts dismantling the furnace. within 3-4 minutes he takes off this little panel, maybe 3x4, think he called it 'limit control'. he goes bad news, you have a cracked heat exchanger, you need a new furnace. mind me, he is looking in a small opening at probably 1% of the heat exchanger.he said rub your finger over and feel how sharp it is. well i did and it was as smooth as a baby's bottom.
after researching by googling "heat exchanger scam" i am 100% certain he was pulling a fast one. told me due to their liability he had to shut the unit down and if i used it the furnace would be sending out deadly carbon monoxide.

i look at it this way, he gave me a quote of 3,000$ to replace the furnace. my guess is 1,500$ is pure profit. what would these guys rahter do, run around and make 20 calls for a furnace tune-up or replace 1 guys furnace.

just google this scam and you'll get a better idea of what these guys are doing. here's 1 of my favorites:
http://carbonmonoxidemyths.com/Myth-1.html. or just go to youtube and watch the fox news report.

Cracked Exchanger Scam

One of the most common furnace repair scams involves homeowners being led to believe their furnace has a crack in its heat exchanger. The scam unfolds when a dishonest repairman is called to inspect an idle furnace. Upon arrival, repairmen act as though they are inspecting heat exchangers, which most homeowners are unfamiliar with. After reaching around inside the exchange, workers inform the homeowner that the unit is cracked and if the furnace is turned on, it could emit carbon monoxide into the home. Whether there is a crack in the heat exchanger or not, dishonest repairmen usually tell victims they, by law, must not turn on the furnace. This often prompts scam victims to pay for a new furnace they may not need.

Read more: Furnace Repair Scams : eHow.com http://www.ehow.com/list_7425898_furnace-repair-scams.html#ixzz2AzvFpkUD

....Please go google: 'cracked heat exchanger' scams. the guy who told you this is a crook. see below:

http://www.google.com/#q=cracked+heat+exchanger+repair+scams&hl=en&prmd=imvns&ei=v8GSUJSlEabo0gHK-YCIDg&start=0amp;sa=N&bav=on.2,or.r_gc.r_pw.r_qf.&fp=e552aaa5db076fa7&bpcl=37189454&biw=1657&bih=780

also: http://carbonmonoxidemyths.com/Myth-1.html

good luck.

This is a good time to point out not all cracked heat exchangers are scams and can be dangerous. But there are a lot of bad contractors out there so it is important to find one you can trust and not move around just to find the best deal because in the long run it usually will cost you more.

IMO