Repair 1 1/2" flue tube

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Roundgunner

Feeling the Heat
Nov 26, 2013
360
Rural CT
I have a small leak in one of the flue tubes. The only thing I can think of is welding both ends shut and hope for a good seal.
 
That sounds semi-major, ouch.

If you had more time & the capabilities, I wonder if the tube would come out if the end welds were ground off? Then put a new tube in & re-weld? But the tubes could also be tied or braced together inside too, maybe, which would kaibosh that idea. (Anybody seen the guts of an Empyre Elite 200? Assuming that's what you have by your sig). Which would leave your idea as the only thing I could think to try, and maybe get you through the winter. I would be quite worried about the rest of the tubes though and how much longer they would last. Actually would be worried about the whole boiler - and how much there is left to weld to.
 
This is a Profab warranted (+$2000 :-( ) replacement boiler with stainless Steel in more parts that failed in the past. The tubes were not one of those parts changed to SS. I'm not seeing rust anywhere, only 3 seasons old, doesn't seem to creosote up like the old one.
I'm in Hanover, CT. Part of Sprague. Half way between Norwich and Willimantic.

Also getting scale under the fan from a small leak up high somewhere. Very little but I will pull out the insulation and find it in the summer.
 
When tubes began to leak in fire tube boilers, sometimes a plug can be made for both ends.
Holes can be drilled through the centers and a piece of allthread inserted with a flat washer and nut spun on both ends. These can be tightened to snug up the plugs to stop a leak temporarily.
 
Ouch.

Your model 200 has 16 fire tubes right? It's rated at 200 K btu max so in theory each tube is able to produce 12,500 btu. If you had to block off one tube you would only be loosing 6.25% of your heat exchange capacity. Looking at it the other way, those 12,500 btu's would have to be adsorbed by the remaining 15 fire tubes. Welding the bad tube shut will probably work just fine. This would increase the delta T slightly (fire side vs. water side). Worst case your stack temps may run a bit higher but I don't really see you "overworking" the remaining 15 tubes. Unfortunately, it looks like your boiler has a limited life span.

I work at a power plant. We have a contractor clean the cooling water tubes in our turbine generator and steam bypass condenser each spring. They are basically huge shell & tube heat exchangers. If they find a thin tube they plug them off before they develop a leak. End result is a tiny loss of overall heat exchange capability.

For what it's worth, I still have not hooked up my indoor model 100. It is an unused but refurbished model 100 that has the stainless lower fire box liner that I got at 60% off. Unfortunately I learned about all the ProFab issues about a year after I bought it.

I delayed my install a few years so my wood supply could season much better. My old 1994 stove LOVES it so we are still barely burning any oil.