Onix Tubing Installation Manual

contacting the subfloor. This will
reduce the heat transfer potential of
the system.
Installation Steps
Installation procedures change from
job to job and are affected by how the
structure is built. Sleeper spacing,
thickness and zoning details are just a
few items that can affect how a
Sandwich application is installed. The
following guidelines and examples
cover the most common installation
conditions. If unexpected circum-
stances arise, please contact Watts
Radiant or a Watts Radiant
Representative.
The most common tube layout pattern
is a single serpentine, although in
some cases a double serpentine may
be used.
Step 1:
Install Manifolds
With the use of Watts Radiant s mani-
fold brackets or manifold mounting
enclosure, secure the manifolds to the
joist or wall enclosure. If the mani-
folds are located in a joist space, make
allowances for the Onix to transfer
through the wall base plate and into
the sleeper system. Follow local code
guidelines when penetrating framing
base (bottom) plates.
Step 2:
Determine Zone
Boundaries
Before Onix is installed, visually
inspect the area to determine the zone
boundaries. This helps determine
where the first circuit is to be placed,
while identifying any obstacles that
may be in the way.
Step 3:
Confirm Tubing
Requirements
Measure the distance from the mani-
folds to the farthest point in the zone.
The minimum Onix circuit must be at
least twice this distance. If not, the
Onix will not be long enough to reach
the farthest point and be able to return
to the manifold.
Step 4:
Sleeper Placement
and Sizing
For this step, gather the following
tools: chalk line, marker, circular saw
and sleepers. There are two main vari-
ations to a Sandwich installation; each
is dependent on how the system will
be insulated. If the system is to be
insulated in the joist cavity, a 3/4"
sleeper should be used with 3/8" Onix.
If the system is to be insulated on top
of the subfloor, between the sleepers,
then the sleeper height needs to be
chosen based on the insulation height
to still allow a 3/4" space for the Onix.
Most systems insulated on top of the
subfloor need a 2 x 4 sleeper with a
3/4" insulation board.
Note: For best heat transfer, Onix
should be touching the upper sub-
floor.
Place a position sleeper around the
zone and all interior walls. This posi-
tion sleeper will help keep the Onix
away from exterior and interior wall
construction. This is important to help
prevent damage to the tubing that may
be cause by wall placement or floor
covering installation, such as carpet
strips or other anchor points.
If insulating below the floor in the
joist cavity, sleepers are usually 6"—7"
wide, leaving a 1"—2" gap between
sleepers.
If insulating between the sleepers,
sleepers are usually a standard 2 x 4
leaving a 14"—16" gap between sleep-
ers. This spacing is based on a stan-
dard 3/4" subfloor being applied on
Watts Radiant: Onix Installation Manual page 27
Onix
2”x4” Sleeper
Board Insulation
Air Gap
3/4” Sleeper
Foil-Faced Fiberglass
Manifold Box
and Cover
Position
Sleeper
Air Gap
Joist side view showing Sandwich application
using rigid foil-faced polyisocyanurate insulation.
Joist side view showing Sandwich application
using foil-faced batt insulation.
Sandwich