316TI vs AL29-4c for chimney liner

shoudabeenaplumba

I'm planning an install of a new 87% + oil boiler that will be vented into an exterior chimney on the North side of the house.  Chimney was built in 1994 clay liner is in great shape, 8x8, 20' approx length.   I think that relining would be a good idea anyway, because it looks like the new boiler will only need a 5" flue.



Is 316ti good enough for low temp exhaust when used on an 87% + oil appliance?  I'm getting conflicting opinions, some telling me Al29-4c is no good for oil, while some say its the only thing. 

Charlie from wmass

Stainless is all we can use

Here in Mass stainless is for oil or gas. Aluminum is for gas some times.

shoudabeenaplumba

The AL isn't for aluminium

Its for Allegeny Ludnum (or something like that) which is a patented alloy of stainless steel.   Both are supposted to be good but AL29-4C is the new kid on the block.  I'm getting the feeling its being pushed just as all new (and expensive) things get pushed into our hands by manufacturers.

CMadatMe

New Boiler

I think since this is a new boiler you should be using the recommendation in the boiler manufacturers manual in the venting section. This will make sure you are not doing anything that may null the boilers warranty.

Unknown

316TI vs AL29-4c

Hi-  Homeowner here that researched this out a while back. Allegheny probably made a mistake calling this "AL" as it can be confused with aluminum liners. Both are stainless steel alloys and from what I learned, apparently 316TI is better for high temp cycles  - Wood, Pellet, Coal  and AL29-4c is better for low temp condensing units due to its chloride  resistance. Here's a link to the Allegheny page  They are very helpful and will answer any questions you have.

- Rod

http://www.alleghenytechnologies.com/ludlum/pages/products/xq/asp/P.14/qx/product.html

shoudabeenaplumba

The manufacturer states

The installer should ensure compatability with the chimney system.  The vent system must be suitable for "low flue gas temperature with possible condensation"

Not a true condensing unit, but running cool enough for the possibility of it.  That to me says stainless liner, but would 316TI be good enough?  I know Oil condensate is corrosive but what about the low-sulfur heating oil that's coming our way?    Is low sulfur heating oil more/less corrosive than gas?  I guess that's a question that will be clearer 5-10 years from now

shoudabeenaplumba

Thanks for the link

Thanks a lot for the link.  I grabbed another off that site:

http://www.bssa.org.uk/cms/File/SSAS2.25-Comparison%20of%20316%20&%20316Ti%20Types.pdf

It helped clarify the differences between the 316 alloys.  From what I gathered 316 has excellent corrosion resistance to Sufur-bearing  condensates.  I'm sure Al29 is better but I don't know if its 2x better.  The titanium is great for strength/resistance at very high temps(900-2100F), which hopefully my liner won't be exposed to!  The money I save with 316ti would pay for the insulation.  I'll put an eye on it every year when I sweep my fireplace liner to see how it goes.  I've got a feeling in 5 years the sulfur in heating oil will be the same as diesel (15ppm) and be much less corrosive.

CMadatMe

Liner

Have had great success with this product when venting Vitola's



http://www.securitychimneys.com/residential/chimneys/Tubinox/

Charlie from wmass

I need to get out more I guess

We have chimney guys install the liners, I was definitely thinking AL was aluminum. I do not like climbing up chimneys on top of roofs, see I was born without wings so being that far above ground bothers me a bit. I have also seen a fair share that were so twisty of chimneys that liners could not fit down through them.

shoudabeenaplumba

Decided on the 316TI

With the money I'll save on the metal I can insulate the liner.  AL29-4C seems to be superior in salt/chlorine-rich enviroments, but 316ti is very good when it comes to oil condensate, which is mostly Sulfur-acidic.  Maybe if I was on the seacoast, or if my boiler shared combustion air with a dryer/laundry room.  I've heard the chemicals in laundry soaps/softeners can be brutal on a typical stainless liner.  Don't keep your pool supplies in your boiler room!