Where does classic ASP store the value for session timeout? I have looked through the code and this classic ASP website isn\'t using Global.asa(so no \"Session_OnStart\") or
Following on from my comments, your Recycling settings need to be set like the following image to make sure the Application Pool will not be reset.

It's also worth setting the "Generate Recycle Event log Entry" so you can see what events are causing your Application Pool to reset. That way you can monitor it in the Event Viewer.
