Insulated chimney liners

Dave_4

The liners are NOT insulated! They are merely stainless and line the existing masonary chimney. The air "void" between the SS liner and existing masonary becomes the "insulater."

In some liners, a ceramic "brick" tile is cast inside the inner and outer aspect of the SS "liner." Wood/coal burners typically use this form. New chimney-ways (like outside and running up the exterior of the structure with hefty "hangers' and mounting hardware to support the weight) are also used for oil, wood or coal.

Were it my home, I'd abandon an unlined (with fire clay or any other form of insualtion) in favor of using a condensing "no chimney required" boiler - rather than invest in a very expensive liner "system."

Doing a high end chimney on a typical oil-boiler - when condensing boilers exist, is akin to putting fertilizer on a weed.

It is rarely warranted or financially justifiable IMO.

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mjj_2

Insulated chimney liners

I'm considering having an insulated stainless steel chimney liner installed in our 2-storey oil-heated house. What is the insulation composed of? I imagine that asbestos has been de-comissioned for insulation purposes.

Bob Harper_2

Oil liners are not required to be insulated per their listing to UL 1777. The liner mfrs. always recommend it but then again, they want to sell insulation. There are two forms of insulation you install with liners. The first is a vermiculite based cementitious mix poured to a 1" thickness around the liner min. Thermix is the most common brand but some liners require their own proprietary mix. The other form of insulation is ceramic fiber blanket. Again, each mfr. will spec their own brand insulation. As previously mentioned, if the rest of the chimney is tight enough, then sealing it top and bottom forms a Dewar's Flask much like a Thermos bottle and air insulates it. This is the method I use here in Philly and have not had problems with condensation even with modern boilers such as Buderus.

I'm not sure where he got that description of factory built chimney but most is solid packed insulation (either mineral fiber or ceramic fiber) with a 300 series stainless inner liner and either a 400 series outer or Galvalume. Some brands have an air cooled chimney and one has an air cooled chimney with a ceramic fiber blanket to keep the flue warm for performance. The listing on factory chimney is UL103, which is a 1,700F rating. If used for solid fuel then the optional High Temp. or HT type chimney should be used, which is rated for 2,100F.

If your boiler is in need of replacement, you might consider switching to a condensing unit and forgoe the chimney altogether. However, if you boiler is ok, then investing in a liner, which carries a lifetime warranty may be a good option.

Check here for a qualified chimney contractor near you:
www/f-i-r-e-service.com .
HTH,
Bob

Jack

another way

IF it will fit into your chimney. I repeat,,,IF... Depending upon the height of the chimney, length of vent connector, firing rate and let us not forget your combustion air situation is to use L-vent of a suitable diameter.

Pellet vent is L-vent rated for oil but comes only in 3 and 4". Metalbestos and Dura-Vent each make an L-vent product in 6,7 (Dura-vent only), and 8" diameters. These are stainless lined galvalum outer for the PV and black painted for the 6,7,8.

Check with your oil company, the appliance manuf, your liner installer and go with the smallest size that will do the job. I'd refer you to Appendix E in NFPA31. It is not a part of the code, I am required to say, but the sweeps I've talked to who have used it say it is spot on.