Cracked heat X ????

[billygoat22]

on the co testing in flue gases, remeber that O2 levels varys with the combustion air temp.

If I set up an oil furnace at 12% CO2 at 20 degrees, at 70 degrees the CO2 would move up to 13.5 or so. Co would also go from little to likely several hundred ppm.

[Javelin379]

On package units or splits that have a plenum you can see the hx in if you get a good bright led flashlight put it in the tubing and look down the plenum or n the package unit sometimes that helps me find those hard to find cracks!!!!!!

[FrostyBeer]

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

How do you clean and vacuum a heat exchanger? Esp. those with tight enclosed burner boxes?

Also anyone have any tips on checking secondary HX's?

[Dr.phil]

I just looked at a 16 y/o ICP (looks like a Heil maybe) condensing furnace that I know has a problem on the center one of it's 3 burners. I can see the flame change with the blower, but I can't find a crack or a hole in any of the places I can get my borescope into. Any ideas on where these fail. I am just not familiar with them.

The round hole where they are connected. The ring pops off, just like the Goodmans. They had a service bulletin on them, and a recall at one time.

[martyinlincoln]

Also anyone have any tips on checking secondary HX's?

I check secondary hx's by pulling the blower and getting in there. White lime scale looking deposits are a dead give away of a leaker.

[mike dixon]

what is this red tagging crap?

[FrostyBeer]

I check secondary hx's by pulling the blower and getting in there. White lime scale looking deposits are a dead give away of a leaker.

What about checking if they're plugged up or blocked?

[FrostyBeer]

what is this red tagging crap?

Disabling a piece of equipment do to unsafe conditions (ex. cracked HX) and slapping a red tag on it saying unsafe, do not operate and whats wrong with it or what have you.

[mike dixon]

We cant red tag stuff here, wish we could

[Gross]

We cant red tag stuff here, wish we could

psh.

[martyinlincoln]

What about checking if they're plugged up or blocked?

Only ever saw one plugged up and the CO in the flue was over 1000ppm.

[Rushmore]

Use a combustion analyzer tool, no matter if it is a newer furnace or not, a cracked Heat Exchanger is never good.

[Rob_in_WV]

I've found several that were sooted really bad and they were cracked too. I always wonder when I see them like that did the crack mess up the combution and cause the soot or did they soot up and overheat leading to the crack? Kinda reminds me of the chicken or the egg saying.