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We diagnose about a hundred or more " sooted " carrier 58 series furnaces every season. We order the primary's and the secondarys, as well as the coupling box. 90 percent of these furnaces were on lp gas. Some were serviced yearly and others were neglected, some were over vented, and excess air readings were too high, or too low. The smell is one you will never forget, which are aldehydes produced from incomplete combustion. I am happy that carrier has redesigned their heat exchanger recently.

Thanks for the info. Much appreciated!!!!!

Originally Posted by chuckcrj

over 9,000 ppm in seconds.

http://www.youtube.com/watch?v=SiMHTK15Pik

Yeah, get used to 58-series Carriers with bad secondaries if you do any kind of resi work ever, gmoliver. You'll get a lot of them. I work at a Carrier FA dealer so I get that joy pretty much every other day.

It really is best to try to steer the customer towards a new one. The 59's have stainless construction.

Either way, Carrier pays for 4 hours of labor to install a secondary. It takes me about half of that while going at an 'unhurried' pace.

Obviously those times in my previous post don't include obtaining the parts and filing the paperwork, which takes more time than the actual repair.

With the help of my cordless screwgun, I can do a secondary in 45 minutes and secondary and primary in an hour and a half.

After you do a few, you figure out all the tricks, such as what parts come out as entire assemblies.

I just changed primary and secondary HX on a 90% Carrier today. It took about 6 hours. The secondary was plugged. CO before the repairs exceeded 2k ppm. After the repairs it was 21 ppm. And the exhaust didn't stink afterwards.

Originally Posted by gmoliver

Just took CO readings and it was off the scale, so i am a commercial HVAC guy, can you give me an idea how hard it is to change out a secondary heat exchanger and time involved?? (Still waiting to hear back from Carrier about warranty details)

Thanks

Good find! Last one I had went over 9,000 ppm in seconds.

That's what I kinda plan on doing, thanks for the help!!!!!!!!!!!

I wouldn't bother replacing the secondary, they changed there design because it was so problematic. Last one I found with bad secondary they gave like 500 or 1500 towards a new furnace I think.

That one smelled terrible on lp.

Just took CO readings and it was off the scale, so i am a commercial HVAC guy, can you give me an idea how hard it is to change out a secondary heat exchanger and time involved?? (Still waiting to hear back from Carrier about warranty details)

Thanks

Customer was complaining, and when I arrived I could smell it. Then I went over to the exhaust and it just smelled rich to me. Hope that helps.

Does the exhaust have a bad smell? Or what led you to believe it was rich?

Thanks for the help!! Will return and take CO readings on exhaust and let you all know the results!!

OK relax, here is some data. Found 4 inch filter very plugged (removed), supply temp. at 100 degrees, return temp. 70 degrees, factory spec is 40-70 delta T. Found gas manifold pressure at 3.5 inch water column. Took CO reading in house and readings were 0. Did not take readings out at exhaust. (Stupid) Did notice pressure tape fitting on gas valve on manifold side connected to combustion fresh air intake.

If what I think you’re talking about is true I would also suspect a clogged secondary. I encountered many carriers with clogged secondary’s and the symptoms were always the same, awful smell at exhaust, extremely high ppm on my combustion analyzer.

The usual amount is 'higher PPM than my TPI is capable of reading'.

Craig1 is probably correct, but you need a flue gas analysis. You needto know how much co is in the exhaust.

you need to provide some intelligible data on this. What were the combustion analysis numbers and what is the appliance doing or not doing? How did you come to this conclusion? By *rich* what do you mean?

Secondary heat exchanger is likely plugged.

Need more info!