Advice on chimney liner options

[RobV]

I am planning on installing a supplemental wood burning furnace in my basement. The wood burner furnace recommends 6” pipe for smoke stack (28 sq. inch draft).

I have a 32 ft. tall brick chimney that has a clay liner in good shape with what appears to be 6”x 10” inner measurements. The gas furnace is now PVC vented separately so most of brick chimney is unused, but an uninsulated 4” flexible pipe currently runs up chimney for hot water heater.

While measuring for chimney liner length, I discovered chimney also has a “witches bend” midway, it appears to be just a couple inches bend – just enough to make life difficult. I tried inserting a 6”diameter plastic windshield washer jug down chimney to check fit and it was very tight even in first few feet, so a 6” round flexible liner is out of the question.

I believe my choices are:

• Not installing a flexible pipe for wood burner and simply using existing clay lined chimney. The result is almost 70% larger opening than recommended for wood burner (47.5 sq. inch draft - based on 6”x10” less 12.5” for 4” pipe).
• Installing a 5.5” flexible pipe (23.75 sq. inch draft) – which may or may not make it past bend in chimney.
• Installing a 5” flexible pipe (19.6 sq. inch draft) – which has a pretty good chance of making it past chimney bend.
• Installing solid 6” chimney liner pipe up from basement for 20 feet (up to chimney bend) and letting last 12 feet vent through current clay liner (47 sq. inch remaining opening for draft). Not sure if this is a viable solution, but it seems like the draw would be well established after 20 feet of vertical pipe and less likely for flue gases to condense or back draft.

Any recommendations?

 

[bholler]

Any recommendations?

Remove the clay liners and install an insulated 6" liner. If the bend is bad it sometimes means opening up the chimney at that location to get the liner through.

 

[RobV]

I don't think removing the clay liners is feasible without tearing down the complete chimney. They were installed at the time the chimney was built and are cemented to each other. And even if I could lift them out the top, I wouldn't be able to pull the the lower 20 feet of liners past the bend.

 

[bholler]

I don't think removing the clay liners is feasible without tearing down the complete chimney. They were installed at the time the chimney was built and are cemented to each other. And even if I could lift them out the top, I wouldn't be able to pull the the lower 20 feet of liners past the bend.

A tile breaker is used to break them up and you shovel them out the bottom we do it all the time in order to make room for insulated liners. You canot vent into that clay liner with the water heater liner in there. You need a separate liner for the furnace to. And to remove the clay you will have to pull the 4" liner out then put it back in.

 

[velvetfoot]

Maybe replace with an electric water heater?

 

[bholler]

Maybe replace with an electric water heater?

There should be room for both liners after the tiles are removed. And there is no issue with doing that. But you cannot vent an appliance into the space around a liner inside the chimney.