Cracked Heat Exchanger in Bakery Oven

[smeq]

I have a customer with a rack-type Hobart bakery oven. It has a flame gun that shoots into a burner chamber then into multiple pipes which form the heat exchanger in the unit. I have visually located a 3" long, very fine crack in one of the multiple pipes after the burner chamber. The oven works but I am sure the crack will only get bigger. The customer wants me to arrange to have the crack welded. Does anybody think this is inadvisable? I'm sure they're going to use it anyway, but wouldn't it be better to at least try to isolate the damage? They do not want to pay for a new heat exchanger or replace the oven.

[fixit52]

What is ther model number of the oven? depending on where you are located it may or may not be legal to weld it, I have seen it done, depends on the overall condition of the heat exchanger as well, if there is signs it is rusting at the seams etc. probably not worth it.

[smeq]

This is a Hobart HO210G2 oven located in central Washington State. No rust, it is an otherwise good looking oven, and other than the crack, a good looking heat exchanger.

[fixit52]

They can get expensive, I have seen replacements anywhere from 7 to 10 thousand dollars. If its allowed to do so in your state, nothing to lose by closing it up with a weld.

[Ovenguy]

Before you condemn the heat exchanger you should use a combustion analyzer to measure the CO in the baking chamber. Do this by slipping the probe under the door gasket with the burner firing. Ideally you should have zero CO but a little is not harmful, say under 50ppm. Some heat exchangers will not release any CO with a crack but others will. It depends on the design.
I'm not sure on the exact procedure for the HO210 but I could find out. Welding is ok if you can get to it but what about where you can't see? Don't back yourself in a corner, when it needs to be replaced it should be.

OSHA requires every oven over a certain BTU to be inspected once a year by a factory authorized services to ensure the entegrity of the heat exchanger. A lot of small places don't do it until they blow the door off of the oven. I have seen two nasty explosions due to failed heat exchangers.