Numerical instability with "control"

[Ervin200008]

Hello all, I’m using FDS version 6.9.1. I use “control” to turn on exhaust and supply, but I always got error message of numerical Instable at certain time (20+seconds). I have a door always open to outside.
When I have the exhaust and supply on at the beginning, everything is fine.

[drjfloyd]

Attach an input file that demonstrates the problem.

[Ervin200008]

Hi, Jason, I eliminated all the blocks imported from CAD, then the fds works, so I guess must be something related with the geometry, not the control settings Ervin Cui, PhD., P.E., (IL, MI, CA) Associate Principal Fire Protection | Life Safety | Code Consulting

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_________________________________________ Wiss, Janney, Elstner Associates, Inc. Engineers | Architects | Materials Scientists 330 Pfingsten Road, Northbrook, IL 60062 direct 847.753.6480 | fax 847.498.0345 www.wje.com<http://www.wje.com/> ***@***.******@***.***> From: Jason Floyd ***@***.***> Sent: Wednesday, January 29, 2025 5:59 PM To: firemodels/fds ***@***.***> Cc: Cui, Ervin ***@***.***>; Author ***@***.***> Subject: Re: [firemodels/fds] Numerical instability with "control" (Discussion #14143) Attach an input file that demonstrates the problem. — Reply to this email directly, view it on GitHub<#14143 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BO7BO6L4THPI7VA2OY4IMZ32NFTNBAVCNFSM6AAAAABWEBKDDWVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTEMBQGEZTGOA>. You are receiving this because you authored the thread.Message ID: ***@***.***>