Best way to balance a new system?
I just installed a new ASHP last week and redesigned/embiggened (thanks, Dr. Bailes, for the blog posts) the return ducts, but the supply ducts were left alone for now. I’ve been using ASHRAE-111 as reference, but have had some difficulty in parsing the best procedure for balancing the system.
My Manual D calls for 664 cfm supply and return. I have 1060 cfm of supply, and 750–800 cfm return. Currently I have the fan speed on medium, and plan on setting that to low which should get me to about 940 cfm or so according to the manual. It is not an ECM, fwiw.
Should installing dampers (none currently exist) on the supply takeoffs and adjusting them to match the Manual D’s room-by-room requirements be the first step?
And this might be a silly question, but if the supply ducts are supplying the stated values in the Manual D for a total of 664 cfm, is it problematic that the returns can take a total of 750–800 cfm? Or do I need to make sure that the supply and returns are equal in cfm?
Finally, if there are any good resources on this process that I may have overlooked I’d love to hear about them.
Thanks for the help!
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