Onix Tubing Installation Manual

For any attachment method, it is
important to secure the tubing to the
rewire/rebar every 12" to 18" on cen-
ter. This will prevent the Onix from
shifting during the concrete pour. (See
Watts Radiant catalog or binder for
more information on fasteners and
tools.)
Application Profiles
and General Details
In slab-on-grade snowmelt applica-
tions, it is important to maintain at
least 2"—3" of concrete covering above
the tubing. More coverage may be
necessary depending on the structural
requirements of the slab. The 2"—3"
coverage is to ensure structural stabili-
ty within the slab, allow for cut joints,
and to allow enough space to float the
aggregate.
Complete encapsulation of
the tubing is important to prevent
stress points from forming on the
slab, which may accelerate cracking
over time.
In brick paver applications
it is important to maintain a 1" layer of
sand or stone dust between the top of
the tubing and the bottom of the paver.
Installation Steps
Manifold locations, final concrete
thickness and zoning details are just a
few items that can affect how a slab
application is installed. The following
guidelines and examples cover the
most common installation conditions.
If a given situation is not covered here
or if unexpected circumstances arise,
please contact Watts Radiant or a
Watts Radiant Representative.
The most common installation pattern
for slab applications is a double ser-
pentine layout, although in some cases
a single serpentine may be used.
Step 1:
Pre-Pour Conditions
Verify all subgrade conditions are
properly prepared, all insulation (if
necessary) is installed according to
design conditions and rewire or rebar
is in place. With orange spray paint,
locate any obstacles that may need to
be avoided. These may include trench
drains or other structural supports that
penetrate the slab, such as hand rails.
Step 2:
Install Manifolds
Locate where the manifolds are to be
installed. In most snowmelt systems,
the manifolds will be located in an
environmentally resistant box and
placed in the ground. Some applica-
tions may allow the manifolds to be
mounted in a structural wall, such as
in the exterior wall of a garage. With
either method, it is important to sup-
port the manifolds in such a way so
they are not damaged during the con-
crete or paver installation.
Drive two pieces of rebar vertically
into the ground at the manifold loca-
tion. With the use of cable ties or elec-
trical tape, temporarily secure the
manifolds to the rebar. Remember to
keep the manifolds high enough to
allow for the thickness of the concrete,
paver or any other structural items that
may need to be installed after the pour.
After the concrete is poured, the rebar
may be cut to free the manifolds. The
manifolds can then be moved if neces-
sary, to fit the final enclosure area.
Manifold Enclosure
Onix
Slab
Rewire/Rebar
Manifolds
Subgrade / Compacted Earth
Snowmelt
Watts Radiant: Onix Installation Manual page 53