User Guide

Installing PureFlow Systems
49
PG-PF 724998 0320 PureFlow System
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 the plumbing system.
This is done by using a return line at
the end of the main hot supply line and
a low-󶈶ow 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 󶈵xture.
Hot return
To fixture To fixture
Hot water supply
Hot
Cold
Hot water supply
Circ pump
Check valves
Cold supply to W/H
Water heater
Typical domestic hot water circulation piping
There are a number of hot water
circulation systems available in the
marketplace that o󶈴er a variety of
options. These systems are ideal for
branch-and-main or combination
systems with spread-out 󶈵xture groups/
󶈶oor plans, as well as for larger homes
using multiple ManaBlocs in a parallel-
type system.
Viega PureFlow PEX 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 return
Hot water supply
Hot
Cold
Hot water supply
Circ
pump
Check
valves
Cold supply to W/H
End cap
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 Viega
PureFlow PEX tubing.
Cold water supply
Water heater
Domestic Hot Water Circulating Systems