bulges and "hot spots" inside 20 year old furnace...do I really need new one?

[nospamever]

I had my 20 year old Carrier forced air furnace tuned up today. The technician snaked a camera up the inside of the furnace. He did NOT find any cracks, but he found "bulging spots" which he also referred to as "hot spots", inside the furnace. He claimed the heat exchanger had these bulges and claimed that this is a sign that it is getting close to developing cracks, and showed me the bulges.

But I wonder if what he showed me really was the heat exchanger....can a camera can really be snaked up inside a heat exchanger?...or was what he showed me something else. I always assumed that a heat exchanger is a tremendously dense piece of metal and that you would not be able to "view inside it with a camera" only "view it from below with a camera". This same cavity could also be seen without a camera by looking into the furnace with flashlight (he had removed one of the panels above where the burners are) What he showed me was was a vertical cavity which had a couple of bulges on the sides of the cavity which were bulging toward the outside. Is that really the heat exchanger he showed me? What does the heat exchanger on a 20 Yr. old Carrier furnace look like and exactly where is it located?

There is also some rust present on the inside of the furnace.

The burners look like they produce a nice blue flame.

The technician is recommending a new furnace based on the age and based on the bulges and rust. Do I really need to be seriously thinking about getting a new furnace at this time because of the rust and bulges, or is it possible this furnace could last several more years? I believe they recommended a new furnace 3 years ago when I moved in although I don't recall anyone showing me the bulges before, but I'm suspecting they could have been present 3 years ago too.

BTW, the company I've been using prefers to install Goodman systems, although they would also be willing to give me a price on another brand that I have in mind which is Carrier. They say that they will warranty both the parts and labor for 10 years on the Goodman, but the warranty on the Carrier would depend on what their warranty is. Is a Goodman likely to last as long as a Carrier?

Thanks,

J.

[Meat Plow]

I used to do furnace checks and was told to sell new furnace installs at any cost short of being fraudulent. The heat exchanger in you furnace is welded steel and is not known to crack or develop leaks at the welded seams. However at 20 years in service I would consider an upgrade if it is your budget to afford it. If it is affordable you would benefit from an increased efficiency in a high SEER rated furnace.

[nospamever]

I'm sure they love the idea of selling me a new furnace even if it isn't really necessary at this time.

Wondering if other metal inside the furnace were to crack and it weren't the heat exchanger cracking per se....would that require furnace replacement?

J

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[Big_Jake]

Sorry Meat,

Paul is right. Furnaces don't have SEER ratings, that is an AC efficiency rating.

I manage several (around 20) townhouses that all have 16-17 year old Carrier furnaces. We have replaced 3-4, and are expecting to have to replace the rest of them over the next 2-3 years because the heat exchangers are failing. Granted, it is generally the secondary heat exchangers getting plugged with crud, but it isn't far fetched that the primaries are failing too, or if you have an 80% efficient model, the primary is all you have.

To the OP -

No, a heat exchanger is NOT a very dense piece of metal. Here is a link to a photo :

Your tech, from above or below, would be looking at the outside of this, getting the same view as you have in the pictures. Typically, on an upflow furnace, the heat exchanger is in the top of the cabinet, but we don't know what you have.

Like Paul said, get another opinion. If you decide to wait, do yourself a favor and spend $30 (or so) on a carbon monoxide detector.

JK

[Meat Plow]

Main concern for safety is the heat exchanger. A crack or weld leak will allow CO from the combustion to mix with the heated air. Not much other metal that would crack or such.

[dpb]

It is possible. The key item is did he do a CO test? The risk in a cracked condenser is flue gas in the warm air stream which is a serious potentially fatal problem. While not as sensitive as a real instrument, a CO monitor could spot a serious problem.

Goodman is one of the lower initial cost units but seems recently (last couple of years from anecdotal evidence) to have upped their warranty periods. What the actual failure rates are for their gas furnace units I don't know but the last CR ratings for A/C units had them at the complete bottom and separated from the rest of the pack by a significant margin. I'd do a little investigative digging before jumping in, particularly if there is an A/C unit involved as well as the furnace.

--

[Superheat]

Get a new furnace before you kill your family you damn moron.

[Superheat]

cracked condensor letting flue gas into airsrtream? LMFAO!

Cr

[<kjpro]

Bulges, hum... a new sales tactic?

Yes

The burner tubes are inside the heat exchanger.

On a 20 year old furnace? No way, get out of here!

That&#39;s nice.

The question as to when to replace would be economics. Where do you live?

And probably present at the time of manufacturing. Try getting someone that&#39;s competent in HVAC.

Any brand will last *if* properly sized, installed and set-up to run with-in the manufacture&#39;s specifications.

[<kjpro]

Heat exchangers are not known to crack?????

I think you&#39;re smoking crack!!!!!!

[<kjpro]

replacement?

Maybe you need to look at a induced draft, inshot burner type of furnace. Things change over the years.

[<kjpro]

A 30 dollar CO detector is crap. Unless you spend a couple hundred dollars on a good one, it&#39;s a false sense of security.

[<kjpro]

CR is a joke for rating HVAC equipment.

[jim]

Heat exchangers do crack, yes you can look inside the exchanger, and usauly there will be a white area around the crack but not always, get a second if you want if he says the same buy it

[nospamever]

Ok, so it sounds like your telling me that they&#39;re trying to BS me about the idea that bulges or curves in the metal are a sign that it is close to the point of cracking. What he showed me doesn&#39;t strike me as appearing to be present by design though.

Anyway, it sounds like I need to be getting a 2nd opinion as to whether the bulges or curves in the metal really mean that the metal is about to crack. Is there anyone you recommend in Northern NJ that knows what they are doing?

Thanks,

J

[nicksanspam]

They do have EERs, like ASHRAE bunnies: if a furnace moves 40K Btu/h with a 400 watt blower, the EER is 40K/(400x3.41) = 29.

If a 2K Btu/h car radiator with 36 W fans moves (140-50)2K = 180K Btu/h from 140 F solar heated water to 50 F air with a 170 W pump, the EER is

180K/(206x3.41) = 256.

Nick

[nicksanspam]

Would you have any evidence for this article of faith?

Nick

[Bubba]

Nick, You can start right here. Its on the front page

level that CO detectors DONT alarm at is the real problem. Happy reading. Bubba

[HeyBub]

The notion of a cracked heat exchanger being a hazard involves the leaking of CO into the living space.

Be aware that, for thousands of years, humans heated their dwellings without benefit of heat exchangers; some still do today.

I grew up in a home with natural gas heaters in every room. The only problem it ever caused me is the inability to tie my shoes. In all fairness, lately I have noticed a difficulty in using complicated mechanical devices (such as a spoon).

Nevertheless, a CO detector (or a canary) is far, far cheaper than a new furnace.

[DerbyDad03]

re: "No, a heat exchanger is NOT a very dense piece of metal."

Granted, I can&#39;t speak to a 20 YO Carrier, but the heat exchanger on my old gas fired unit was one heavy, honkin&#39; mass of metal, looking somewhat similiar to an old water filled radiator. By far the heaviest component of the entire furnace.