Closely-spaced tees: Install tees with straight piping (min. pipe diameter lengths as
per Table 8 ), with tees maximum 4 pipe diameters apart with no restrictions between
fittings.
Heat migration: To prevent heat migration on secondary loops extending vertically
to a load above the primary loop (especially where head loss is low): install check
valves on both supply and return of secondary piping, or install a check valve in the
supply piping and create a thermal trap in the return piping (min. 18"(46 cm) drop).