HearthStone 8220 Owner's Manual page 11

requirements
Alcove
Maximum alcove depth is 48"/122cm
Minimum alcove height is 96"/ 2439cm
Minimum alcove width is 63"/ 160cm (with single wall connector)
Minimum alcove width is 58"/ 147cm (with double wall connector)
CHIMNEY CONNECTOR
CLEARANCE TO COMBUSTIBLES
SINGLE WALL CONNECTOR DOUBLE WALL CONNECTOR
Hearthstone Quality Home Heating Products, Inc ®
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Model 8220