How do you avoid cracking a VAV reheat coil connection when tightening piping?

Stop and shut down/isolate the water side as needed. Thin coil connections need backup wrench support; a twisted or cracked internal coil/header needs proper mechanical repair or replacement.

['VAV hot-water/reheat coil connections are not heavy pipe nipples to muscle around. If a fitting is tightened without backing up the coil connection, the internal copper/header can twist and crack inside the box.', 'If it leaks, stop adding torque. Protect the space, isolate/drain if directed, open the casing if needed, and have the repair done by the responsible trade/person. Future connections need a proper two-wrench/back-up method and manufacturer/submittal direction.']

Stop if

• Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

Check

• A cracked coil can flood ceilings, damage finished spaces, delay startup, and require coil replacement.

Steps

• Stop tightening when the coil fitting moves or the casing starts twisting.
• Check whether water is active and whether the loop needs isolation/shutdown.
• Find leak location: external fitting, coil connection, internal header, or casing.
• Document the damage and notify foreman/mechanical piping lead.
• Use backup wrench/support method on any remaining connections.

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