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Ruuduser 03-21-2009 09:20 PM

Heat Exchanger Inspection DIY
Is there a DIYer method for heat exchanger inspections. My furnace is a model that has been know to get leaks. I don't see an easy way to get at the exchanger without tearing the system apart.

Assuming we (the DIYers) don't have camera tubes, is there another way.

Accurate CO meters to a few PPM would be to expensive.

How about some sort of visual inspection with the flame?

Would the jet of blue flame change if there was a leak - maybe when the fan turns on? Seems hard to visualize since the inducer seems to really pull the flame into the tubes. Would probably need to be a big leak to effect the flame? :huh:

beenthere 03-22-2009 03:01 AM

Often it will effect flame if there is a leak, but not always.

hvaclover 03-22-2009 09:28 AM

Been is right. A small crack does not drastically change flame color. A big one can. The color change would be subtle to obvious.

As pros we use the flame merely as a symptom, not as a final conclusion on a heat exchanger inspection.

Your best bet is too have it checked professionally.

yuri 03-22-2009 09:54 AM

When they crack they usually open up larger quickly. Then the flame blows out the front of the burner area and trips the rollout switch as the blower pressurizes the heat exchanger. When you work on lots of units you get to know their history and where they crack. If the flame changes a lot when the blower comes on then it is a red flag for a crack.

beenthere 03-22-2009 10:49 AM


Originally Posted by yuri (Post 248194)
If the flame changes a lot when the blower comes on then it is a red flag for a crack.

True many times.

I've also seen more then one condemned.
Because the tech didn't take notice that the air filter bracket on the outside of the furnace. Had no door. An it was allowing the blower to pull the flame back when the blower started.

And there was no crack in the HX.

Thats why I prefer if a tech doesn't get paid by performance.

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