CCS Flue Liner Types & Installation 4

Question 1

When relining a chimney used by a high-efficiency gas furnace (Category IV appliance), which liner material is required?

Accepted Answer

AL29-4C or equivalent high-alloy stainless steel

Answer

Category IV appliances produce positive-pressure, moisture-laden, acidic flue gases requiring AL29-4C or equivalent corrosion-resistant alloy liners.

Question 2

What is the purpose of a top plate (liner top plate or rain cap plate) in a flexible liner installation?

Accepted Answer

It secures the liner at the chimney crown and supports the rain cap

Answer

The top plate anchors the liner at the chimney crown, seals the annular space, and provides a mounting point for the rain cap.

Question 3

A masonry chimney serves both a fireplace and a gas water heater through separate flues. A sweep finds a hole connecting the two flues inside the chimney. What is the primary hazard?

Accepted Answer

Carbon monoxide from the water heater can enter the fireplace flue and the living space

Answer

Interconnected flues allow CO-laden exhaust from the gas appliance to migrate into other flue passages and potentially into the home.

Question 4

Which installation detail is critical when terminating a flexible liner at the appliance connector tee at the base of the chimney?

Accepted Answer

The liner must be sealed to the tee with listed components to prevent flue gas leakage

Answer

The connection between the flexible liner and the appliance tee must be sealed with listed components to prevent combustion gas from leaking into the chase or living space.

Question 5

In a masonry chimney, the annular space between a new flexible liner and the original flue tile should be:

Accepted Answer

Filled with listed insulation or left open per manufacturer instructions

Answer

The annular space may be filled with listed insulation for performance improvement or left open as the manufacturer specifies; non-listed insulation materials are not approved.

(CCS) Certified Chimney Sweeper Practice Test

(CCS) Certified Chimney Sweeper Practice Test

CCS Flue Liner Types & Installation 4