Onix Tubing Installation Manual

For certain industrial or commercial
projects the spacing may be greater.
Onix is generally installed on either
rewire/rebar for concrete slab applica-
tions, or to the subfloor for thin slab
applications. Closer spacing may be
used in areas of high heat loss, such as
an exposed wall with a high percent-
age of glass. 9" o.c. spacing is some-
times preferred in bathrooms, kitchens
and entries. Closer tube spacing, up to
6 inches on center, may also be used in
areas that have a low thermal conduc-
tivity, such as areas with thicker than
normal concrete or dense floor cover-
ing such as a carpet and pad.
It is important to note that simply dou-
bling the amount of tubing does not
double the floor s heating output. The
floor s ability to deliver heat to a room
is based on the floor s surface temper-
ature. The amount of radiant tubing
and fluid temperature controls this sur-
face temperature. More tubing, or
tighter spacing may allow for the same
surface temperature to be reached at a
slightly lower supply fluid tempera-
ture.
Watts Radiant s RadiantWorks design
software generates a specific nomo-
graph for each room in the design.
Nomographs convey several key fac-
tors associated with a room, such as
tube spacing, floor surface tempera-
ture, floor heating intensity, mean
(average) supply water temperature
and back and edge loss values.
Nomographs are essential to any radi-
ant design. More information on how
to read and use a Nomograph can be
found in the Appendix.
Perimeter Banding
Four, five or six inch Onix spacing is
frequently used along outside exposed
perimeter walls. These high-density
spacing areas are called perimeter
bands and tubing is generally spaced
at half the primary spacing. Banded
areas range in width from two to eight
feet, with the wider bands generally
used in front of taller exposed walls
with a high percentage of glass. A
good rule of thumb is to use a perime-
ter band width of 50% to 75% of the
height of the wall. Most banded widths
will be 4 ft. wide or half a standard
wall height.
For example, in a home with 12" spac-
ing in the main floor area, a 6’ 8" patio
door would have radiant tubing on 6"
centers a minimum of 40"—48" in front
of the door.
Tools and Materials
Required
It is a good idea to have all materials
present and in good working order
before beginning an installation. The
following is a list of the most common
items needed for a typical slab instal-
lation.
1. RadiantWorks Reports.
These reports help ensure the proper
amount of tubing is installed in each
area, along with the correct manifold
size.
2. Onix tubing and corresponding
Onix Clamps.
Each Onix TorqueTite clamp will
require an in.-lb. torque wrench for
installation, while the SelfTite
clamps need a pair of SqueezeTite
Pliers. See manifold assembly sec-
tion for more details. The number of
Onix coils on the jobsite should cor-
respond to the number listed in the
Zone List report.
Watts Radiant: Onix Installation Manual page 37
Onix routed below expansion joint into subgrade.
Radiant Slab
Radiant Slab
Expansion Joint
Onix
Rewire / Rebar
Protective Sleeve
Subgrade / Gravel
Expansion Joint
Onix
Rewire / Rebar
Subgrade / Gravel
Onix sleeved at expansion joint with foam insulation or PVC conduit.
min. 6”
min. 2”
Caution: Do not exceed
the minimum bend
radius of the tubing.
min. 2”
min. 6”
Concrete Slab