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Apprentice answer

Why does flex duct kink right at a register boot collar

1st YearFlex Duct, Boots, Grilles & DiffusersStandard Correction

Flex does not like sharp unsupported direction changes. Add a rigid angled boot/elbow where needed, then connect the flex so the core stays round and open.

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Plain-English answer

When a boot collar points the wrong way for the branch path, pulling flex hard to make the turn can crush the wire core. The room may get weak airflow even if the duct is technically connected.

Use a rigid sheet metal elbow, boot shoe, or approved angled fitting at the collar first, then attach the flex to that fitting with a smooth path and proper support. Keep the flex stretched, round, and free of kinks.

Ask Foreman

The flex at [location] is kinked right off the register boot. I think it needs a rigid 45/angled boot first so the flex stays open. Do you want me to change that connection?

Verify before acting

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

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