Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Compression Check

Indicated compression pressure
Refer to Testing and Inspection for more details.

Lowest cylinder within 75 percent of highest
The indicated compression pressure is considered within specification if the lowest reading cylinder is within 75 percent of the highest reading.