HVAC return pipe ask? New, l4 seer, 2 1/2 ton, variable speed Amana Heat Pump have...
New, l4 seer, 2 1/2 ton, variable speed Amana Heat Pump have l4" intake return pipe. New tech we hired to check installing tech's work says we should enjoy 18" return pipe. Looking for any web site that would hold a chart to back up 2nd tech. Also, any comments greatly appreciated.
Answers: With the duct size calculator, a 2.5 ton ac part =1000cfm so for proper size with .5 static pressure it is 16 inch for 700 fpm velocity. Less than that the ac will not be as restructured. The 18 inch would work it would be quieter. For more info about ducty system design, check out the duct page at www.hvac-for-beginners.com
14"Diameter return is correct.