Does this happen offten?

[Doug Edwards]

Ditto to what's been said. Like anything else in Home inspections. Unless you can physically see it, you are pretty much guessing. It is a "visual inspection". Again, many HI today are getting onto thin ice and analyzing or troubleshooting equipment / systems to the level of being well beyond the scope of a home inspection. I am not saying this to snap anyone's garter or to embarrass anyone. I am alarmed by this trend because in the rush to be competitive and to provide that "little something extra" many HI are venturing into areas where they may not have the background, experience or training to make these kinds of calls. I am not concerned when someone with years of working in a trade goes out on a limb but when I see a brand new inspector (again, no one in particular here) make calls of this nature I literally cringe. Another element of this trend is the general public comes to expect this from ALL home inspectors and the paradigm is changed to the detriment of all HI and the HI industry. (i.e. Home inspectors quoting prices for repairs, etc.)

[John F. Bell]

Mr. Anderson has the best thought for finding the cracked x changers. Watch the flame when the blower comes on. If it is inordantly disturbed, the exchanger is leaking positive pressure from the blower. then check it with your sensitive C.O. sniffer. In my state we are bound by law to immediately disclose a dangerous situation to the seller.

[John F. Bell]

Doug, you are right, us old guys with many licenses and thousands of inspections may feel confident about stepping out there with an opinion, if you ain't sure, say so and let somebody that is sure have a look. It is bad for business to kill your costomers with C.O.

[klott]

Originally Posted by dandersen

There are very few indicators outside of visually seeing the crack in the exchanger that you can safely base an assumption of a cracked heat exchanger.

About the only obvious indicator would be when you turn on the furnace and watch the fire when the blower comes on. When the fire rolls out at you, that's a good indication of a cracked heat exchanger.

I have seen this also, plus I look at the burner flames, not the pilot, I've seen them WhOOsh on start up, no flames at some ports, slow to start, and even rattle like crazy. But I think everyone agrees on one thing, it's dangerous.

[jbreazeale]

I try to make it as simple as possible. Observe all the usual things like rust, pilot and burner flame, etc. An older unit I am automatically suspicious. If there are any doubts, my CO detector is in good working order. Then I refer it, without stating definitively "the heat exchanger is cracked," whether I THINK so or not. From there, I let the pros handle it, even though I have several years experience working on gas furnaces. As someone said in an earlier post, the only sure-fire way to know is to pull it.