Fire Tube Heat Exchangers taking hold

SpeyFitter

It appears as though ACV has been marketing their fire tube heat exchangers to more than a few manufacturers with successful results. If I'm not mistaken, the majority of these exchangers are made with 439 stainless steel which I'm guessing is significantly cheaper than Nickel carrying stainless steels in the 300 series, especially 316 L, and even more so with 316 Ti. I've noticed pricing with boilers that carry this new exchanger seems 'very competitive' lately as well from more than a few manufacturers. Lochinvar, IBC, and now NY Thermal (Trinity Fire Tube - just saw an add for it today) on top of the already existing Triangle Tube are boilers that I know of that now have models with this heat exchanger. It seems like Giannoni has some competition, and I wonder if Viessmann's heat exchanger will survive a redesign? It's a good heat exchanger but I'd imagine the Germans would have to acknowledge the electricity reduction from going with a heat exchanger with siginficantly less pressure drop.

TonyS

400 series

Scott The reason you would use 400 series stainless is because of the weldability.

400 series(FERRITIC) stainless expand at a rate much closer to regular steel.

This is why it is used in firearms,engine parts,ect.

If you look at the robotic welding on a CVA exchanger you will start to appreciate this modern art.

316 and 304 stainless(austenitic) is more common and usually used in exchangers that are wrapped, stamped or low temperature brazed.

Without the ability to robotic weld you cant build a self cleaning, low head pressure exchanger.

I dont know how familiar you are with welding alloys but this will give you a better understanding.

CMadatMe

Perception

That heat exchanger your seeing on other boilers is not the same as triangles (ACV). ACV went out and found a new supplier due to the polish company that made their hx was have quality control issues as well as could not deliver a hx larger then 399. The polish company turned around and started selling the hx to the others. ACV went out and found a new supplier.

Kestrel

Lochinvar?

Is the HX in the new Lochinvar Knight WHN line the same as the TT, or other?  Have you found significant quality issues with the non-TT firetubes?

EricAune

As I understand it...

The original heat exchanger for the TT is the same exchanger now found in the new Knight wall hung models.  TT has contracted with a different supplier to build similar exchangers with hopes that QC and availability are not an issue.  Again, this is how it was explained to me...by a salesman. 



Regardless of the who and why, this design has been nothing but wonderful in every application I have installed it in.  I have not installed the new Knight units but have been using TT's for many years.  The design of this heat exchanger, along with well thought out system piping and controls, has eliminated more than a few components needed on a lot of "usual" installs.  Couple that with lower electricity use (fewer and smaller circs), less annual maintenance and its a win win for most buyers.