CCS Flue Liner Types & Installation 3

Question 1

What is the minimum clearance typically required between a UL-listed metal liner and combustible framing in a masonry chimney chase?

Accepted Answer

0 inches — no clearance required within a masonry chimney

Answer

When a listed flexible liner is installed inside a masonry chimney, no additional clearance from the masonry is required because the masonry itself provides the separation.

Question 2

Which type of mortar is recommended for repointing terra cotta flue tile joints?

Accepted Answer

Refractory mortar rated for high-temperature use

Answer

Refractory mortar is designed to withstand the high temperatures and thermal cycling inside a flue, unlike standard Portland cement mortars which can crack and fail.

Question 3

When installing an aluminum liner, which appliance type is it approved for use with?

Accepted Answer

Category I gas appliances only

Answer

Aluminum liners are approved only for Category I (non-positive pressure, flue gas temperature above dew point) gas appliances due to their lower heat and corrosion resistance.

Question 4

What is the function of an insulation blanket or poured insulation fill around a flexible stainless liner?

Accepted Answer

It raises flue gas temperature to improve draft and reduce condensation

Answer

Insulating the liner keeps flue gases hotter longer, improving draft and reducing the condensation that leads to creosote buildup and liner deterioration.

Question 5

A chimney sweep discovers that a liner section junction has an offset of more than 30 degrees inside an existing masonry chimney. What is the correct course of action?

Accepted Answer

Install a flexible liner to navigate the offset

Answer

Flexible liners can navigate offsets that rigid sections cannot, making them the appropriate solution when significant angular changes exist in the flue path.

(CCS) Certified Chimney Sweeper Practice Test

(CCS) Certified Chimney Sweeper Practice Test

CCS Flue Liner Types & Installation 3