heat xchanger cut off or leave on

[flip67]

It heating time again we will all be looking at heat xchanger asking ourselves should we cut gas off if it is cracked last year my company left it up to us as tech to make that decison to cut off or leave on just want to no what you guys thank and what you are going to do this year i thank we as tech should have a common way of going about it so we can best serve the customer and not back stab each other let get togather on this guys and have a good heat season ps. What size crack is to small to cut off or is a crack a crack in gas should turn off

[JayATS]

A crack is a crack and the safety of your customer is in your hands. Turn it off, and if the customer turns it back on after you leave the liability is in his/her hands now.

[Gross]

a crack is a crack.....what size of a family has to die from co poisoning before you decide on a rule?

[rruss69]

call gas company they will shut off

[DirkRoper]

Interesting topic. We have condemned any time we find a crack. I've always felt that a crack could indicate a larger problem where a whole chunk could conceivably fall out. Plus, our gas utility will red tag anything that has any crack. So it kind of puts us in a delicate position in liability terms.

Imagine my surprise when I watched Jack Rise's fall maintenance training on the ACCA website and listened to him wax eloquent about how it's the utilities' lawyers that are making the call and that many cracks can be ignored. I'm disturbed that I am either going to have to condemn furnaces that aren't actually bad, or endanger people's lives.

There is a class for cracked heat exchangers that I think I'm going to send my service manger to so I can get better answers.

[gregp]

the gas off at the appliance, and tag it. Document everyting on your service ticket and make sure the customer SIGNS IT! What they do after you leave you have no control over. Take a picture of the valve off and tag in place for your records. :.02:

[BRnGT]

the gas off at the appliance, and tag it. Document everyting on your service ticket and make sure the customer SIGNS IT! What they do after you leave you have no control over. Take a picture of the valve off and tag in place for your records. :.02:

Great Idea.. I have found a few cracked HE's..and shut them down..And never charged for the call..who's to say that if something happens..like CO poisoning that they won't say So +So worked on it...if something happened i don't think i could sleep...:gah:

[chuckcrj]

Lennox Pulse, Rheem drum furnace, Trane voyager.

The only 3 I can think of right now that have a positive pressure in the heat exchanger which would allow exhaust gases to enter the airstream.

All others have a negative inside the heat ex so any leak would simply suck more air into the flue gases.

I would never walk away from a furnace I knew was cracked without tagging it and shutting it off. It really isn't very likely for someone to get CO poisoned from a cracked heat ex and I have had customers that would use their cracked furnaces over night or weekend til we could get a new one in.

How many of you guys test for CO in the flue pipe? Did you know ANSI requires you to red tag any vented appliance that is producing over 400 ppm CO (air free)? A furnace with a good HX producing high or rising CO is a lot more dangerous than a furnace with low CO and a crack in the HX. But very few techs take a CO reading.

[BRnGT]

And you would not believe some of the readings we have gotten from smokers sitting in the house..Air out the house and get a completely diffrent reading...:cheers:

[dunkman]

Speaking of red tagging... Does anyone have a source for "red tags"? Is there a company that makes a "unsafe to operate, etc." tag? Does Uline make them? We've just been using a wire tag with our company sticker on it.

[hotrodrob]

Speaking of red tagging... Does anyone have a source for "red tags"? Is there a company that makes a "unsafe to operate, etc." tag? Does Uline make them? We've just been using a wire tag with our company sticker on it.

contact a local printing company. we have red tags with our company logo and information printed up along with pm stickers and company info stickers to put on units.

[chuckcrj]

One thing I like on the red tags we use is a line that reads something like; "In the event there is an incident, we may be required to provide your insurance company with a copy of this red tag"

This makes it more serious, obviously if something happens because they turned a unit on that was red tagged and something happens, the insurance co. would deny coverage.

A 3 part red tag is good, that way one copy you give to the homeowner, one goes on the appliance, and the original goes back to the office file.

[Tommy1010]

It really isn't very likely for someone to get CO poisoned from a cracked heat ex

famous last words:whistle:

[chuckcrj]

famous last words:whistle:

Can you find a single documented case? I have searched several times and haven't found one.

[Tommy1010]

Can you find a single documented case? I have searched several times and haven't found one.

just the fact that someone i look up to like you admits that its "not likely" means too me, that "it could happen"

and probably has, but as stated "all cracked heat exchangers get red tagged"

[chuckcrj]

just the fact that someone i look up to like you admits that its "not likely" means too me, that "it could happen"

and probably has, but as stated "all cracked heat exchangers get red tagged"
Yeah, its not worth taking a chance.

[Snapperhead]

I've never heard of anyone dying from a cracked exchanger. Maybe if you lived in a 6x6 room i suppose it might get to you.

I would think a few headaches that just wont go away would be a good sign something is wrong....

But yes it needs to be replaced asap.

[beenthere]

CO poisoning/high levels in a house from a cracked heat exchanger isn't from the CO getting into the supply air stream through the crack. But more from the crack allowing supply air to push the CO out through the burner compartment, and into the return through air leaks, or unsealed air filter brackets/slots.

Depending on the position and area of the crack. You can have a very low or 0 PPM CO reading in the flue, but still be putting out CO through the burner compartment.

[Gross]

I've never heard of anyone dying from a cracked exchanger. Maybe if you lived in a 6x6 room i suppose it might get to you.

I would think a few headaches that just wont go away would be a good sign something is wrong....

But yes it needs to be replaced asap.

we had a row home burn to the ground....yelled and screamed that im a scam artist....turned it back on when i left.two weeks later took out her house and 4 others...cracks can get really bad really quick

[Gross]

Speaking of red tagging... Does anyone have a source for "red tags"? Is there a company that makes a "unsafe to operate, etc." tag? Does Uline make them? We've just been using a wire tag with our company sticker on it.


you can make your own from a print shop...i use the ones from NCI....kind of expensive...but hey....ill spend a dollar for a 8000 dollar replacement any day!

[Gross]

Lennox Pulse, Rheem drum furnace, Trane voyager.

The only 3 I can think of right now that have a positive pressure in the heat exchanger which would allow exhaust gases to enter the airstream.

All others have a negative inside the heat ex so any leak would simply suck more air into the flue gases.

I would never walk away from a furnace I knew was cracked without tagging it and shutting it off. It really isn't very likely for someone to get CO poisoned from a cracked heat ex and I have had customers that would use their cracked furnaces over night or weekend til we could get a new one in.

How many of you guys test for CO in the flue pipe? Did you know ANSI requires you to red tag any vented appliance that is producing over 400 ppm CO (air free)? A furnace with a good HX producing high or rising CO is a lot more dangerous than a furnace with low CO and a crack in the HX. But very few techs take a CO reading.


depends on an air venturi or not and how big of a crack....if it can suck enough air in through the crack...you'll have BIG problems through all burners....prob a large bit of roll out too.

[second opinion]

Interesting topic. We have condemned any time we find a crack. I've always felt that a crack could indicate a larger problem where a whole chunk could conceivably fall out. Plus, our gas utility will red tag anything that has any crack. So it kind of puts us in a delicate position in liability terms.

Imagine my surprise when I watched Jack Rise's fall maintenance training on the ACCA website and listened to him wax eloquent about how it's the utilities' lawyers that are making the call and that many cracks can be ignored. I'm disturbed that I am either going to have to condemn furnaces that aren't actually bad, or endanger people's lives.

There is a class for cracked heat exchangers that I think I'm going to send my service manger to so I can get better answers.

Jack would be correct. The heat exchanger classes are marketing products. If you are really interested in training for your technicians, send them to a "combustion analysis class" with a competent technical trainer and have them get a thourough knowledge of the combustion process. It is all about chemistry and physics as to what can and can not happen.

[DirkRoper]

Jack would be correct. The heat exchanger classes are marketing products. If you are really interested in training for your technicians, send them to a "combustion analysis class" with a competent technical trainer and have them get a thourough knowledge of the combustion process. It is all about chemistry and physics as to what can and can not happen.

I'll look into that. I have one technician who is NCI certified. He took the trouble (and expense) to do that himself before he came to work for me. Do you consider this to be a good program? Are you at liberty to recommend others, either here or by e-mail?

[Gross]

I'll look into that. I have one technician who is NCI certified. He took the trouble (and expense) to do that himself before he came to work for me. Do you consider this to be a good program? Are you at liberty to recommend others, either here or by e-mail?


Best combustion course out there...your whole shop should get nci cert'd

[second opinion]

I'll look into that. I have one technician who is NCI certified. He took the trouble (and expense) to do that himself before he came to work for me. Do you consider this to be a good program? Are you at liberty to recommend others, either here or by e-mail?

yes and yes

[Tommy1010]

depends on an air venturi or not and how big of a crack....if it can suck enough air in through the crack...you'll have BIG problems through all burners....prob a large bit of roll out too.

exactly

when enough fumes draft back and trip the rollout, it would make sense that you were probably spewing at least some ppm's of co into the airstream before the rollout tripped

[Glennhvac]

There is a big dif between a crack and a gap. Look how many thousands of those Lennox duracurves are out there that have been cracked for decades and would still hold water. Yes I have seen a few open up eventually.
Cracks like that I note it and tell the people about it and suggest we monitor it until they are ready to replace.

When I first stated 38 years ago I worked for one of "those" places for two years so maybe I am a bit hesitant to start red tagging, locking gas, calling gas company or painting an x on their front door. If it is unsafe or causing a bad flame/draft I do shut it down. Sometimes if it's an end section I have even plugged that orifice for a day or two to at least let them have some heat.

To comment on cracks themselves not causing co to enter the house is not quite accurate. I have seen fumes pouring out of draft hoods once that blower starts. The other issue with a cracked exchanger that can be worse than a bit of co is how that thing burns or ignites when that blower comes on. Flames rolling out of an attic or closet unit not good. Also a constant running blower with a crack in the right/wrong place can cause one heck of a delayed ignition.

[chuckcrj]

There is a big dif between a crack and a gap. Look how many thousands of those Lennox duracurves are out there that have been cracked for decades and would still hold water. Yes I have seen a few open up eventually.
Cracks like that I note it and tell the people about it and suggest we monitor it until they are ready to replace.

When I first stated 38 years ago I worked for one of "those" places for two years so maybe I am a bit hesitant to start red tagging, locking gas, calling gas company or painting an x on their front door. If it is unsafe or causing a bad flame/draft I do shut it down. Sometimes if it's an end section I have even plugged that orifice for a day or two to at least let them have some heat.

To comment on cracks themselves not causing co to enter the house is not quite accurate. I have seen fumes pouring out of draft hoods once that blower starts. The other issue with a cracked exchanger that can be worse than a bit of co is how that thing burns or ignites when that blower comes on. Flames rolling out of an attic or closet unit not good. Also a constant running blower with a crack in the right/wrong place can cause one heck of a delayed ignition.
Fumes pouring out of the hood when blower comes on is a sign of the CAZ going negative, not usually from any crack.

[Glennhvac]

Fumes pouring out of the hood when blower comes on is a sign of the CAZ going negative, not usually from any crack.

Yes but ever see those 50 year old muellers that were about 8' x8' crack in the back end? You are correct but that does not happen within a second or two of the blower turning on nor does it suddenly crop up. Again, it depends on the furnace construction and where the crack is. If you get cracks up top with a restricted a coil and it starts pumping out quick.

[chuckcrj]

Yes but ever see those 50 year old muellers that were about 8' x8' crack in the back end? You are correct but that does not happen within a second or two of the blower turning on nor does it suddenly crop up. Again, it depends on the furnace construction and where the crack is. If you get cracks up top with a restricted a coil and it starts pumping out quick.
Wow, a crack that big would certainly do it.

[Glennhvac]

Wow, a crack that big would certainly do it.

oops. Wrong sentence structure. Furnace 8x8 not crack.:gah:

[mdelliott]

A crack is a crack and the safety of your customer is in your hands. Turn it off, and if the customer turns it back on after you leave the liability is in his/her hands now.
couldn't have said it better.

Having sat in on the heat exchanger experts class in philly last week, all I can say is WOW. There are probably tons of cracks that I've never even noticed before.

To anyone interested in serving your customers. I highly recommend this class. It goes over the proper way to examine all different heat exchanger designs. They all have certain stress spots and they are all more likely to crack in these areas.

Turn it off for the love of god.