Install Instructions

Table Of Contents
Viega PureFlow System Design Considerations
31 of 88
IM-PF 724596 1021 PureFlow Water System (EN)
6.4.2 Home Run Systems
Water Heater Placement
The Viega ManaBloc should be as close as possible to the water heater
to minimize extra water from being stored in the larger hot water supply
lines between the ManaBloc and water heater.
The longer the hot water supply line is, the greater the volume of water
needed to purge through that line and faucet before hot water is available.
This creates water waste and longer hot water delivery times.
Proper Water Distribution Line Sizing to Each Fixture
This is crucial for overall system performance. If you oversize a
distribution line to a 󶈵xture (½" PEX line supplying a sink instead of a ⅜"
PEX line) you are essentially doubling the volume of water being stored
in that line. It can take roughly twice as long to purge an oversized line
compared to a properly sized line.
Length of a Distribution Line Run to Each Fixture
This is just as important as properly sizing each distribution line. Length
of a distribution line run can drastically a󶈴ect the performance of a Viega
ManaBloc system. The longer the line is, the more water being stored
within it. Therefore, it will take longer to purge it out before hot water can
reach the 󶈵xture. The ManaBloc should be located somewhat central
to your 󶈵xture groups, keeping within 60 feet or less of each 󶈵xture for
maximum performance.
If this cannot be accomplished with one ManaBloc, multiple ManaBlocs
may be required. Place one at each end of the home to split the
distribution line distance between them (see "8.5 Multiple ManaBloc
Installations" on page 43).
The 󶈵xture is what dictates water 󶈶ow (federally mandated, governed by
code). The tubing applies a friction loss dictated by its size and length.
Therefore, as long as you do not undersize a distribution line or run it
excessive distances (60 feet or greater), the system will perform properly,
maintaining su󶈷cient pressure and 󶈶ow.
6.4.2.1 Design Factors for Home Run System