Hi Jack, I highly recommend "overdesign and throttle back" with any wave soldering system. The factory specs are to be considered guidelines, but not absolute. I believe Hollis recommends 600CFM @ 1" S.P. per port, X 2 ports totals 1200CFM @ 1" S.P. This is probably adequate, but as one is probably aware, the real world presents challenges that aren't always considered. Most buildings in North America experience barometric pressure differences caused by heating (winter) and air conditioning (summer) that effect the performance of vent systems. In addition, as you add more vented equipment to the building, you begin to add to the problem by causing the building barometric pressure to go further negative relative to the outside. You can experience this phenomena when you slowly open an outside door and hear/feel the air whoosh in through the opening. I've seen it so bad that the door cannot stay closed under the hingespring force! So, what I'd do is get a good size blower like Grainger's 7C562 and throttle it with blast gates like Mc Master-Carr's 1822K315 located on each port of the machine. These will help balance the air flow entrance to exit as well. Be sure to follow "good layout" practices when installing the vent, i.e., no "sharp" 90 degree turns, use 2 45 degree elbows instead, etc. If you'd like to discuss this in further detail, feel free to give me a call. Regards, Ed Popielarski QTA Machine 10 Mc Laren, Ste D Irvine, Ca. 92618 Phone:949-581-6601 Fax: 949-581-2448 Cel: 949-337-2578 WWW.QTA.NET --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------