Mixed use retail and Condo project. Each condo has a seperate 40 gal WH without recirc. HW FU calcs for each condo requires a 1-1/4" line from heater decreasing in size as fixtures are supplied. Showers have 3/4" line. Showers designed for 2.6 gpm shower head. 1.5 gpm installed. Pipe sizing -vs- velocity -vs- flow calcs out to a 90 second delivery time from WH to farthest fixture. Actual delivery time is 3 minutes or more. Water pressure is fine.

I know in a typical residential application a 1" or a 3/4" HW from the heater and 1/2" at fixtures is typical. Since this went thru building department code had to be followed.

Are the pipes over sized causing the long delivery time? Any input would be appreciated.