Cracked heat X ????

[trouble time]

A cracked heat exchanger can be a bad situation. But with the newer furnaces that are essentially negative pressure, is there any harm? Today I found a heat exchanger, 16 years old, very rusty on the inside with seems that are 1/8 to 1/4 inch separated. No indication of a crack, but it made me nervous just looking at it. I brought the customer down to the furnace and explained that although I could not find a definitive crack, my gut feeling is that if I pulled the furnace out, I would find one. I used the bore scope and could see signs overheating. I red tagged it.
Questions. How far do you go to find a crack if you suspect one? What do you let go?

[DavidsHeatAC]

Id look at it if it were my own. The risk of running it would be too dangerous and i would tell the customer that. Its all about safety and my family comes first. I always go with my gut feeling. Sometimes the naked eye can't see everything but your gut instinct is usually right.

[Chuck]

I don't red tag them just for rust, but I certainly stress to the homeowner that their furnace will be unsafe shortly and now would be the perfect time to replace it.

[Gross]

Furnaces have all ways been in a negative pressure... It's not co spilling out of a crack that should worry you. It's flue gases backing up due to air being Pulled in brought the failure causing high levels of co or flame roll out. According to the AGA....ANY failure is well enough to red tag a furnace

[Chuck]

Furnaces have all ways been in a negative pressure... It's not co spilling out of a crack that should worry you. It's flue gases backing up due to air being Pulled in brought the failure causing high levels of co or flame roll out. According to the AGA....ANY failure is well enough to red tag a furnace

A rusted heat exchanger is not a failure if there is no "visible crack or hole".

[tinknocker service tech]

rusted hx needs a good cleaning and vacuming out then check to see if a crack is there
have seen many a rusted hx lennox and carrier mostly but could not find ant cracks just poor draft in most cases

[HuNGRYTeCH]

I like to poke at rusty heat exhangers with a screw driver in a few spots, if it is copmpromised you will usually find out much quicker than taking it out. If I don't put a hole in it and I still am uncertain I will explain to the customer and let them decide if they want to pay me to take it apart and stress the safety factor.

[Chuck]

I like to poke at rusty heat exhangers with a screw driver in a few spots, if it is copmpromised you will usually find out much quicker than taking it out. If I don't put a hole in it and I still am uncertain I will explain to the customer and let them decide if they want to pay me to take it apart and stress the safety factor.

Just don't let the homeowner see you jabbing their hx with your screwdriver!! LOL

I do that too.

[trouble time]

Thanks for the feed back. I like to think that I stress safety.

[Maximum19]

These are good posts. Now you should also possibly consult with Jim Davis at NCI. He is the leading furnace expert in the industry.
Also if you use a combustion analyzer you will find that with a properly combusting furnace there is a very low risk of CO going into the home from a crack. But a low level CO monitor is a lifesaving investment for the H.O.

[stickinit2thman]

A cracked heat exchanger can be a bad situation. But with the newer furnaces that are essentially negative pressure, is there any harm? Today I found a heat exchanger, 16 years old, very rusty on the inside with seems that are 1/8 to 1/4 inch separated. No indication of a crack, but it made me nervous just looking at it. I brought the customer down to the furnace and explained that although I could not find a definitive crack, my gut feeling is that if I pulled the furnace out, I would find one. I used the bore scope and could see signs overheating. I red tagged it.
Questions. How far do you go to find a crack if you suspect one? What do you let go?

You go as far as you have to or untill the customer says replace.

[Maximum19]

You go as far as you have to or untill the customer says replace.

Lol... You may think that, but there are several companies in major class action law suites because of that mindset.

[kimosobee]

I understand what you mean about gut feelings on whether a furnace is safe or not but if you go by gut feelings and not evidence or CO readings than your relying on speculation and fear that you might have instilled to the unknowing homeowner. Just my opinion .

[walterc]

I like to poke at rusty heat exhangers with a screw driver in a few spots, if it is copmpromised you will usually find out much quicker than taking it out. If I don't put a hole in it and I still am uncertain I will explain to the customer and let them decide if they want to pay me to take it apart and stress the safety factor.

I do that too, but some go to far.

I was on a second opinion call for a hole in a HX. Natural draft furnace. I looked inside and saw the hole through rusty but thick metal. Someone took a screwdriver and I guess a hammer and beat a hole in it. The customer said they heard the hammering.
I left it up to them and advised them on how to proceed.
The most difficult part to prove it is not actually seeing them do it, but to assume they did by the noise.

I've also seen the low speed wire cut to the motor so they would have to call them back to check the heat- as well as the white LV wire cut, thermocouples cut and so on.

Pretty pathetic.

[DavidsHeatAC]

Well, an experienced tech can go on gut instinct because ive see it time and time again. Usually can tell right off if its just surface rust or rusted all the way through. Just get a Trane with a 20yr warranty on the Heat x and you will never have to worry.

[Maximum19]

Since That warranty really makes that metal last longer right.

Better make sure it is combusting right with low o2 or any heat exchanger will rust through.

[Lusterh&a]

I looked at a furnace this afternoon a goettl, yes that is spelled correctly, ok it is a spark ignition pilot with draft fan and the pilot is not getting pulled into combustion chamber and that chambers flame is not as clean burning as the others. My snake camera broke this summer but who thinks it is a cracked heat x

[trouble time]

I understand what you mean about gut feelings on whether a furnace is safe or not but if you go by gut feelings and not evidence or CO readings than your relying on speculation and fear that you might have instilled to the unknowing homeowner. Just my opinion .

I understand this and it is why I started this thread. I do not want to put fear into my customers. I just want to do my job to the best of my abilities, at the same time keep my customers safe even if they do not want me to.

[DarrinB]

I have been on a couple of 2nd opinions already this fall for cracks. One was and one very definitely wasn't. Same company different techs. Seems to be the thing again this year.

I like to sell equipment too, but I will only do it honestly though.

This is why it's so important to find a good and honest company and stick with them. Don't get drawn in by any super cheap offers you hear in the media. The only way to really save on this stuff is to get good equipment from a good company that will install it correctly and then take care of it.

[billygoat22]

the gama/aga standard for inspecting hxs does include 50% loss of the metal as a failure, not too sure how you'd test that.

I check every furnace before repairing, since whoever touched it last will be blamed for any injuries, dust, "new" noises, the water heater breaking, the stove not lighting right, etc.

Some of Trane's gas packs are negative pressure gas valve/positive pressure hx design. the gas is injected into the intake of the combustion blower and blown through a screen (I think) into the comb chamber. -.02" wc on the gas valve.

I don't use a screwdriver for the "you did it" reason. WD40 sprayed on one side will bleed through any holes in rust spots.