Hearth and Home Technologies BIR50 operating instructions SL-300 MH842 Celing/Roof Thimble Cont’d

North Star

EPA Certified Fireplace

9. SL-300 MH842 Celing/Roof Thimble (Cont’d)

	CHIMNEY
FLASHING	FLASHING
	PLATE

THIMBLE

EXTENSION

SCREW

NAIL

ADJUSTABLE

EXTENSIONTHIMBLE HOLES

Figure 16A - Installing an MH842 Configuration 3

10 Securing the Chimney System

When offsets and returns are joined to straight pipe sections, they must be locked into position with the screws provided (outer only), using the predrilled holes. To prevent gravity from pulling the chimney sections apart, the returns and the chimney stabilizers have straps for securing these parts to joists or rafters. See Figure 16B.

NOTE: You must provide support for the pipe during construction and check to be sure inadvertent loading has not dislodged the chimney section from the fireplace or at any chimney joint.

FIRESTOP

STRAPS

11.Marking the Exit Point of the Roof

Locate the point where the chimney will exit the roof by plumbing down to the center of the chimney. Drive a nail up through the roof to mark the center. See Figure 16C.

12.Cutting out the Hole in the Roof

Measure to either side of the nail 7-1/4” and mark the 14-1/2” x 14-1/2” opening required. This is measured on the horizontal; actual length may be larger depending on the pitch of the roof. Cut out and frame the opening. See Chapter 25 of the Uniform Building Code for Roof Framing Details.

Be sure to maintain a 2” minimum air space between the chimney section and the roof.

13.Assembling the Chimney Sections Through the Roof

Continue to add chimney sections through the roof opening, maintaining at least a 2” air space.

OPTIONAL ADDITIONAL SUPPORT

JOINT BAND (OPTIONAL)

Figure 16C - Ceiling/Attic Construction

Figure 16B - Offset/Return with Stabilizer

WARNING!

Maintain a minimum of 2” air clearance to all parts of the chimney system at all times! Failure to maintain this 2” air clearance will cause a structure fire.

WARNING!

When chimney sections exceeding six feet in length are installed between an offset and return, structural support must be provided to reduce off-center loading and prevent chimney sections from separating at the chimney joints.

480-1081 16 4-03