Cracked Heat Exchanger? Carrier 58SXC

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  #1  
Old 11-29-12, 02:54 PM
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Cracked Heat Exchanger? Carrier 58SXC

I have a Carrier Deluxe Condensing Furnace model 58SXC (WeatherMaker). The exhaust smells and the power company tested it and said the exhaust have very high levels of CO. No, we are NOT OPERATING THIS UNIT.


I had a repairman/installer come out to look at it. He says he is unable to viw the exchanger, but "it must be cracker". The flame is clean and DOES NOT blow back. Some rust is visible to the extent you can view into the exchanger. He says I need a new furnace. Yes the unit is 17 years old; however, I plan to sell the house in two years so I do not want to NEEDLESSLY replace it.


Is a cracked exchanger really the only possibility here? It seems to me that high levels of CO would be from incomplete combution and not an exchanger, but what do I know. (I would like to have some one expain to me how the flames can look great and still have CO. Obviously, I have high levels but how, from where).


Do I need to pay another contractor to look at this, only to tell me the same thing? Do I need a new furnace?
 
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  #2  
Old 11-29-12, 02:56 PM
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The heat exchanger has a 20 year warranty ? Some units have 10

Not sure about the secondary heat exchanger, may be 20 or lifetime?

Contact your local dealer
 
  #3  
Old 11-29-12, 03:17 PM
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Thanks Boiler nut,

The repairman was a Carrier Dealer and he did not mention any warranty deal. Oversight? However, he did say that a heat exchanger replacement was a dog and very expensive. Other thread have said warranty is parts only, there in lies the rub. I will diffently look into it.
 
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Old 11-29-12, 03:26 PM
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<< Is a cracked exchanger really the only possibility here?

>>


No, it's not.

<< It seems to me that high levels of CO would be from incomplete combution and not an exchanger, but what do I know.

>>

The carbon monoxide IS from incomplete combustion which can have any of several causes. a cracked heat exchanger is one of those possible causes.

<< I had a repairman/installer come out to look at it. He says he is unable to viw the exchanger, but "it must be cracker".


>>

He's guessing. His guess that it must be the heat exchanger is wrong. It COULD be the heat exchanger, but since he didn't bother to do a good diagnosis of what might be causing the problem, he doesn't know.

<< (I would like to have some one explain to me how the flames can look great and still have CO.

>>


That's easily possible, even fairly common. It's more common to have yellow tipped flames or other visible flame defects causing CO problems, but it also happens that ordinary appearing flames can be producing CO ---- too much primary air can cool the flame too much which prevents complete combustion, and burners that are even slightly overfired can produce excessive CO ---- and Carrier condensing furnaces are susceptible to that in my experience.

<< Do I need to pay another contractor to look at this, only to tell me the same thing?

>>

You need a crackerjack repairman who really knows his stuff and is willing to do the job you need done, which is to analyze the problem and determine it's cause and what can be done to correct it.
 
  #5  
Old 11-29-12, 04:27 PM
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Thanks Seattle.

I guess the question is, How do you find a "crackerjack" repairman.

If the symptom is high CO in the exhaust, what SPECIFIC TESTs should I ask or expect to be done to properly diagnois this problem?

Gosh it is hard to be a consumer. Your contractors can all be incompetitent or criminals and we never know. And, of course, they knew this too. Which can just make them lazy and not incmpetitent or criminal. And of course there must be good ones too, but some bloody hard to find. And because most seem to fall in the former cateories, the consumer distrusts or doubes the good ones.

Thanks.
 
  #6  
Old 11-29-12, 04:40 PM
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With that model of furnace it is VERY likely that the secondary heat exchanger is failed. Remove the blower motor to view the secondary heat exchanger. If you see what marks from above and or on the blower assy it is VERY VERY likely the secondary is failed.
 
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Old 11-29-12, 04:49 PM
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I read that carrier secondary heat exchangers are regular steel coated with plastic - when the plastic coating fails, the acidic condensate causes corrosion.

Other manufacturers always used stainless steel.
 
  #8  
Old 11-29-12, 05:00 PM
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"If you see what marks ..." What are what marks? Thanks.

Is removing the blower assy a big job? Why did the repair guy not do this? Doubt bother, I know.

Do you know if the Carrier Warranty / lawsuit issue would make this a dal to pursue for me. You probably don't know as no one can know every model and every lawsuit. I suspect if I follow-up on this I will get a run around from the dealer and or Carrier directly. .....
 
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Old 11-29-12, 05:24 PM
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Often removing the blower assembly is not too bad of a job.

If you are lucky, you will see a couple of screws holding the blower assembly in place. Remove the screws and the blower assembly may sliiiide right out.

Sometimes you may need to remove the circuit board or some other stuff.

No guarantees, but are you feeling LUCKY today?

If you find the secondary heat exchanger to be OK, you can celebrate by oiling the blower motor as long as you have the blower assembly out of the furnace. Many times you will find one oil port that is easy to oil. If so, there's another that requires that you pull the whole blower assembly apart to get to it, but it probably needs to be done badly.

You might have a permanently lubricated blower motor, which has no oil ports.

The blower motor should be oiled every five years.
 
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Old 11-29-12, 05:42 PM
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The secondary has a poly propylene coating as I remember...it can flake off and plug the drain too, and cause the unit to lock out.
 
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Old 11-29-12, 06:10 PM
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"What marks" should have read water marks
 
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Old 11-29-12, 06:11 PM
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Not sure what you mean by "lock out", but before we knew the unit was smelling it would not come on at all, then it did, then it did not, then it did and continued now for three weeks or so. Our problem now is teh high CO (4000+ ppM) in exhaust. So........ could be the exchanger and 'flaking off as you say and locking out.
 
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Old 11-29-12, 07:15 PM
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4000 ppm co is A LOT of carbon monoxide! The furnace should be left off until it is repaired or replaced.


Cold? Tough. Cold is better than dead.
 
  #14  
Old 11-29-12, 07:20 PM
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I have to agree with SP!............
 
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Old 11-29-12, 08:22 PM
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Crack assessment is only done when looking at the existing situation. Cracks do not go away and they only get longer and wider with time and temperature and they can change in hours.

Do you live in the house with a cracked exchanger? You may get lucky and wake up to decide more seriously about the consequences.

A newer furnace is not a waste of money since the home will be worth more with a new furnace if you do actually try to sell. If not, you have bought some great insurance instead of dangerously putting off replacement.

Dick
 
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Old 11-30-12, 08:18 AM
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On a condensing furnace like yours, you may need to remove the drain trap to pull the blower.
 
  #17  
Old 11-30-12, 10:46 AM
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So when you say the exhaust, I picture there is combustion exhaust which goes right outside, and I picture warm air exhaust which is the air being warmed and circulated through your house thus heating it.

Now, it is more than obvious that if the warm air from the furnace into your house has such high levels, that is serious .

I guess what I'm wondering, and it isn't clear here, if the combustion exhaust has high CO levels, I can see where that would be bad for efficiency, but is that a danger to the home occupant as well?

Since the exhaust is going right outside it seems not.

Bottom line, when I see "Exhaust" I wonder if it's combustion or recirc exhaust.

Am I missing something?
 
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Old 11-30-12, 11:09 AM
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Suppose you were moving into a place and the landlord said that mustard gas was circulated through the house, but not to worry since it was contained in sheet metal ductwork 1/32" thick that was secured by screws.

Happy with that?

As a practical matter, it's not unusual to find a furnace that's making a lot of carbon monoxide to be circulating some of that through the dwelling spaces. There are lots of ways that can happen.

The short answer is that it is unsafe to operate a furnace with significant amounts of CO in the combustion gasses.

The gas utility I used to work for required any appliance we discovered with 120 PPM CO to be shut off and the gas supply to the equipment capped off if CO levels exceeded that amount unless we could make repairs on the spot to get those levels down.
 
  #19  
Old 11-30-12, 11:18 AM
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Yes, I have already stated the FURNACE IS OFF. IS suppose I can state this in all future posts. thanks
 
  #20  
Old 11-30-12, 11:23 AM
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The furnace is off!

YES, of course the furnance is off. Do people read these threads?

The issue is not wheather I am trying to kill myself, but how do you diagnosis this problem, and whether it can be repaired or needs to be replaced. And I suppose how to deal with contractor to do a complete diagnosis (and to know what that is) and to get a contractor to do the best FOR ME, not the easiest for him or the most profitible for him.
 
  #21  
Old 11-30-12, 11:29 AM
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YEs, it is capped off. I have three space heater and a fireplace and it is only 40 degrees outside, so Ihave time to get this right.

This issue is complicated by the fact that there is a 100% warranty on the secondary heat exchanger, PARTS AND LABOR. Therefore, it is very important to me to not just get a "oh well, I did not look at crap, but you need to spend $3000 on a new furnace" answer from a tech. It is critical to KNOW what the problem is.

So how do I find out?
 
  #22  
Old 11-30-12, 12:39 PM
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"How do I find out". Do you read the thread? Pull the blower and look for water marks on the secondary and or blower assy. Have a contractor do this. Call a factory tech. Get it figured out some way or another. This is really a dangerous situation that should be handled by a professional. We can't tell you who a good professional in your area is because we don't live there. Call your gas company. Call someone and get help.
 
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Old 11-30-12, 02:20 PM
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Yes, I read. You say this is dangerous. Well do you read? REally dangerous? The bloody gas is CAPPED -off. How many time do I have to spell it out? So is it dangerous becasue of a sheet metal cut? As for tell me what to do, yes I understand .. pull the bloody thing apart and look. BUt you ahve not answered teh question as to what other tests should be done before the trouble of dismantling the thing.
 
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Old 11-30-12, 02:28 PM
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Yes, I am calling "professionals", most don't know anything, and want to sell you a furnace. Not very useful. Proof. The first guy says buy a new furnace. Does he tell me that the exchanger is under warranty? No. Does he tell me I can get a $650 credit against a new furnace? No. DOes he tell me that a secondary heater exchanger repair would be free? No. So you wonder why I might like to know exactly what is going on and SPECIFICALLY WHAT TO ASK these supposedly PROFESSIONAL? A guy needs to know MORE than the professional in order to fit this stuff correctly and cheaply. SO we apeal to other people for ideas and direct.

But it is difficult when people scream about shuting the furnace off when the first Freaking Thing I post is "THE BLOODY FURNACE IS OFFFFFFFFFFF" Becaseu I know the first thing people will say is "are you stupid, are yu trying to kill yourself ... blah blah blah. BUt moorons don't read the posts so you have to explain the previously stated obvious over and over and over again.

Of course I can not ask any questions and just fork over $1000 more than necessary. Then why ask any question and why should anyone answer unless they have an inferiority complexand wish to feel important. No, the point is people can help one another avoid criminals and stupidity. But it takes a little patience and effort.

Thanks all who are patient and helpful.
 
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Old 11-30-12, 03:12 PM
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Sorry for the excessive number of typos.
 
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Old 11-30-12, 04:46 PM
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yes I understand .. pull the bloody thing apart and look. BUt you ahve not answered teh question as to what other tests should be done before the trouble of dismantling the thing.
The ONLY way to confirm anything is to view it. There are NO tests that will tell you proof positive if the the heat exchanger is failed other than viewing it. Pulling the blower is VERY easy (at least for a pro). Without viewing the heat exchanger and examining it you can NOT prove or disprove a failed heat exchanger.

Asked and answered.
 
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Old 11-30-12, 05:38 PM
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Yep. Life sucks sometimes.

And I fully agree with you there are too many marginally trained and skillful people who call themselves repairman but don't do a good job for people and often are mainly interested in selling people new equipment.

My suggestion for dealing with that----

Talk to friends, neighbors and relatives to identify a contractor you can trust and who does good quality work. Do that BEFORE you need help.
 
  #28  
Old 12-01-12, 01:04 PM
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AFter teh tech left I called the service manager to ask a few more questions. He said just to look at the secondary exchanger would take 3 to 4 hours. True or Fase, I can not say. In looking at the blow assemby it does look like a PITA. Clearly doable, but.... I then called another Repair house, and the gal on the phone knew all about the warranty/law suit issues, rules for repairs, documents needed to claim the warranty, options for repair vs replacement, and said that they would only need an hours service call and a rquired Carbom test (for an exact $50) in order to determine if it is the secondary and to document it for warranty.

This is impressive and the kind of service I would expect from "an authorize dealer". (The original guy was a authorized dealer as well)

She also told me about a $400 utility rebate. I would have looked into it myself, but thought it appropriate for her to know about it and I appreciated. All of this makes one have more confidence.
 
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Old 12-01-12, 01:08 PM
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When I say tests, I mean are there any tests which would have made sense to preform on the furnace before one defaults to guessing it is heat exchanger? This would seem logical to me. Much of the furnace components are right there in the open and test could be run. Perhaps and perhaps likely, if the furnace is running and the flames look normal, blah blah, then there are no tests. Just wondering if anyone knows. Did the first guy to look at the unit do ll he could do, which was limited to looking at the flame and looking for water. Should he have done a presure check (I am guessing presures don't change after proper install, but things age and orifices (spelling) could enlarge), or ....... some other test.
 
  #30  
Old 12-01-12, 01:14 PM
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Ask before you need help. Good idea, but you know alot of people never buy a new furnance or only buy one. Does that really tell you anything. Good experience, bad experience could be just luck and not a reflection on the actual quality of the job. Or one tech at the firm is good and the other not so good, will you get the good one? Or employee change over.

I always find it fun how someone will say Doctor so and so is great, then they have a second procedure with the same doc and all of a sudden, not so great! We all get luck and then rave about the pro, but what is really the reality of the over all quality.

I am jsut say that for services which we so very infrequently engage it is very difficult to know what you are going to get even with advice from friends. An auto mech, is some one different in that you have more runs at the apple. You have a guy do the brakes, then an alternator, and then struts, and then a starter. After a while you can tell if he is upcharging you or knows what he is doing. A furnace every 20 years???
 
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Old 12-01-12, 02:08 PM
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An hour would usually be ample time to pull the fan assembly and inspect the secondary heat exchanger.

If it's OK, the fan assembly should probably be pulled apart and cleaned as needed and the fan motor oiled if it has oil ports. That would take another 45 minutes or so but might save you from replacing the blower motor.

"tests" for a bad heat exchanger? Well, the only one I think is good is if you can see fan interference with the burner flames when the fan turns on.

There are lots of other tests, but mostly they are used to condemn a furnace and sell people new equipment. If the heat exchanger is bad, I'd want somebody to SHOW me where the damage is so I can see it.

Unfortunately, I fear too many repairman can see a $100 bonus if they see a bad heat exchanger on a service call and sell someone on buying a new furnace.

As I say, sometimes life sucks. Your only real defense is an honest and competent repairman.
 
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