Honeywell RTH3100C Guide D'installation page 12

Installation Guide
Mount wallplate
Drill holes at pencil-marked locations:
1.
3/16" holes for drywall
7/32" holes for plaster
2. Use hammer to tap anchors
into holes until flush with wall.
3. Place wallplate over anchors
and insert screws. Check level
if desired, then tighten screws.
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