PEX Installation Manual

IM-PF 724596 0416
54
Typical domestic hot water circulation piping
16.10 Domestic hot water circulating systems
A hot water circulation system can be incorporated
into most plumbing systems and works by
constantly (or periodically throughout the day on
a timer) circulating hot water through the main hot
supply line of your plumbing system.
This is done by using a return line at the end of the
main hot supply line, and a low-flow pump (usually
near the hot water tank). The circulating system keeps
hot water readily available throughout the main hot
water supply line, eliminating the need to purge the
entire line before hot water is present at the fixture.
There are a number of hot water circulation systems
available in the marketplace that offer a variety of
options. These systems are ideal for branch-and-
main or combination systems with spread-out fixture
groups/ floor plans, as well as for larger homes using
multiple ManaBlocs in a parallel-type system.
ViegaPEX Ultra can be used in recirculating domestic
hot water plumbing loops, provided:
1. The plumbing loops shall operate with water
temperatures of 140°F or lower, as required by most
model plumbing codes.
2. The recirculating loop is for supplying hot water more
quickly to the xture.
3. The tubing is marked as rated for “continuous
recirculation” as evidenced by the ASTM F876
certication marking PEX 5306 (CL5).
Continuously Recirculating Hot Water Plumbing Loops
Hot
Cold
Hot Water Supply
Cold Water Supply
Water Heater
Check
Valves
Hot Return
End Cap
Hot Water Supply
Cold Water Supply
If the ManaBloc must be
mounted farther than 8 ft. from
the hot water source, the
ManaBloc may be supplied
from a domestic hot water
circulating loop using ViegaPEX
Ultra tubing.
Cold Supply to W/H
Circ
Pump
Hot Water Supply
Check Valves
Circ Pump
Hot
Cold
To Fixture To Fixture
Water Heater
Cold Supply to W/H
Hot Water Supply
Hot Return