CCS Flue Liner Types & Installation 5

Question 1

Which factor most directly determines whether a round or oval flexible liner should be used in a relining project?

Accepted Answer

The shape and dimensions of the existing flue opening

Answer

The shape of the existing flue opening dictates liner shape; oval liners are used in flues too narrow for an equivalently sized round liner.

Question 2

What is the main disadvantage of using a smaller-diameter liner than the appliance manufacturer specifies?

Accepted Answer

Insufficient draft can cause backdrafting and CO spillage

Answer

An undersized liner creates excessive flue resistance, reducing draft and risking backdrafting that allows CO-laden gases to enter the living space.

Question 3

During a video inspection, a sweep observes that clay tile liner sections are no longer aligned and have shifted laterally. This condition is called:

Accepted Answer

Offset separation

Answer

Lateral misalignment of liner sections is called offset separation, which creates ledges that trap creosote and gaps that allow flue gas bypass.

Question 4

A gas appliance is being downsized from a 120,000 BTU unit to a 60,000 BTU unit in a home. What liner concern should the sweep raise?

Accepted Answer

The existing liner may now be oversized, increasing condensation risk

Answer

A significantly oversized flue for a smaller appliance produces lower flue gas temperatures and velocities, increasing moisture condensation and reducing draft.

Question 5

When installing a flexible liner down from the top of the chimney, what technique helps prevent the liner from kinking at bends?

Accepted Answer

Using a stiff inner guide rod or nose cone attached to the leading end

Answer

A nose cone or guide attached to the leading end of the liner helps it navigate offsets and reduces the risk of kinking during top-down installation.

(CCS) Certified Chimney Sweeper Practice Test

(CCS) Certified Chimney Sweeper Practice Test

CCS Flue Liner Types & Installation 5