Hearth and Home Technologies FB-ZC-S - Manual (Page 6)

Heat & Glo • FB-ZC-S • 2019-910 Rev. G • 11/08 6
D. Inspect Firebox
Surface cracking or crazing of fi rebrick material is normal
and expected. The following types of cracks are acceptable
and do not require replacement of the unit or the fi rebox:
• Cracks that do not propagate entirely thru the material.
• Light fracture lines or “spider-webbing” on the surface of
the material.
• Cracks that are less than 1/32 in. wide and less than 3
in. long.
• If cosmetically unacceptable, such cracks may be
repaired with the SRV-PACK service kit. See Service
Parts List.
Cracks that are unacceptable:
• Cracks greater than 1/32 in. wide and 3 in. long are at
risk of growing.
• Cracks that penetrate entirely through the firebrick
material.
Inspection for cracking should be run when the appliance
is cool. Cracks tend to close as the appliance heats up.