Stainless steel chimney liner with OR without insulation.

Stacy_2

J Carta

Thanks for you note about the chimney liner with or without insulation.

You discussed the situations where the liner is too big for the flu or too small for the flu. What happens if it's just the right size? Would you recommend the insulation or is it unnecessary in a place like Seattle.

Thanks,

Stacy

Stacy_2

Stainless steel chimney liner with OR without insulation.

I will be having a Viessmann Vitogas 50 ECD-S-155 Boiler placed in my home.
In order to switch from my old 85 year old boiler to the new high efficiency boiler, I will be having my chimney lined with high grade stainless steel for the exhaust.

The chimney expert recommends placing insulation around the stainless steel liner. He states it maintains more of a constant temperature for the steel, especially helpful on cold days. I live in Seattle. He states this is the standard in most other colder areas of the country, although not yet in Seattle.

The boiler person has never known of a chimney liner needing insulation in the past. He thinks it's likely unnecessary but will bow to the recommendations of the Chimney person. However, he was concerned that the steel might get too hot and ultimately become more brittle in the long run.

Would any one know what is optimal?

Thanks,

Stacy

j carta_3

liner

if your chimney is too big for the liner it is best to insulate the space between the liner and the chimney it will really help get the draft going quickly because it warms up quickly-you should follow the recommendation made by the chimney co-they will have to warranty it -if the flue is really too big and the liner is much smaller it can condense on the outside of the liner in the cold chimney flue you just lined and it will not warm up quickly and you could have problems -especially if you are in a very cold climate

Eric Johnson

Don't worry

Don't worry about the heat. Stainless steel chimneys can take a lot more heat over a longer sustained period than yours is going to see. Modern catalytic wood stoves routinely put 1,000 to 2,000 degree gas into Class A stainless steel chimney liners with no problems. And insulation is always a good idea, for the reasons already stated.

Bob Harper

liner for condensing unit

Since that unit is condensing, you will want AL29-4C stainless alloy only. Accept no other alloys. As good as 316Ti is, a high efficieny condensing unit will rot it out. For Category III & IV units, the liner/ vent must be listed to UL 1738, which means it can take positive flue gas pressure and withstand the corrosion to a certain std.

Seattle isn't too brutal but you do get cold. Insulation would help a little if you were worried about draft but you aren't with that unit. You aren't worried about a chimney fire as you would be with woodburning. Because that unit WILL condense, you're not going to stop it. Therefore, I'd be more concerned about condensate collection than insulation.

HTH

j carta

liner

if it was me i would insulate with the liner- -but again follow the recommendation from the company installing the liner-thats there business- there are benefits to insulating as others have stated -good luck

Boilerpro_5

The Vitogas is a non condensing boiler

With a cast iron heat exchanger and draft hood. If you speak to the chimney liner manufacturers, they always recommend that the liner be insulated. However, this costs a little more money and, at least in my area, no one has ever heard of insulating a liner. Also, around here almost all contrators use cheaper flexible aluminum liners, so the need for insulation is even greater than a stainless liner. Funny, almost no one ever asks the homeowner if they want something better than the cheapest!
Sad, sad, sad!

Boilerpro

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