Installation Guide

18 INSTALLATION
Installation
Check to ensure the heating cable(s) purchased match the power supply (i.e., 120 V with 120 V or 240 V with 240 V, or 240 V with 208 V). Check to ensure you are
not exceeding the 15 amp limit of the thermostat. Compare the purchased cable area to the floor area to be heated. Important: The cable area purchased should be
as close to the heated area as possible, without going over. The heating cable CANNOT be trimmed or shortened to fit.
It is recommended that the installation of the DITRA-HEAT system is photographed (e.g., heating cable layout, floor temperature sensor placements, transition splice
location, end splice location, and wide view of the room) for reference with future renovation work and troubleshooting. The homeowner/end user should retain these
photos for their records.
Before the heating cable is removed from the
spool, conduct the first set of required tests and
record values in the heating cable tests log (page
30). If a break or damage is detected during the
tests, return the heating cable to the original place
of purchase.
1
Thread the heating cable cold lead through a conduit
(where required by code) from the base of the wall
to the thermostat electrical box. Floor temperature
sensors may not be threaded through the same
conduit as the cold lead.
2
3
Embed the heating cables between studs, at a
spacing of 3 studs (3-1/2" – 9 cm). Closer spacing
may result in overheating and damage to building
structures. A wider spacing (e.g., 4 studs) will not
provide sufficient power to warm the floor to the
desired temperature. Exception: a two-stud spacing
is used when connecting the 240 V cable to a 208
V power supply. See page 25 for more information.
4
Use care not to damage the cables during
installation, particularly before the cables are
embedded in the matting.
The maximum allowable length of a single run is 10 ft (3 m);
the cable must be turned or a u-shaped "jog" created at
this point (see image above).
5
Install the thermostat sensors evenly spaced between two cable runs, at a distance of at least 24" (610
mm) from the wall. Mark the sensor location on the DITRA-HEAT and cut the matting to recess the sensor.
It is recommended to temporarily remove the heating cable from the area while cutting the matting.
It may be necessary to temporarily secure the sensor to the floor with thin-set mortar or adhesive (e.g., KERDI-FIX or
hot glue). Embed the sensor wire in the matting without overlapping or crossing the heating cable.
6
Once the heating cable and floor temperature
sensor installation is complete, retest and record
values in the heating cable tests log (page 30).
7
Mark where the cold/hot splice will be placed, cut
the DITRA-HEAT or DITRA-HEAT-TB matting, and
insert the splice. It may be necessary to temporarily
secure the splice to the floor with thin-set mortar or
adhesive (e.g., KERDI-FIX or hot glue).
Once the heating cable cold lead and remote
sensors are threaded to the thermostat electrical
box, install a metal protection plate at the base of
the wall. This will help prevent any damage from
fasteners (e.g., nails, screws, etc.) in the future.
Notes:
• Make sure to leave space for inserting the floor temperature sensor(s).
• Heating cables may not touch, cross over, or overlap one another.
• Minimum spacing from:
• Walls is 3" (75 mm) • Fixed cabinets is 2" (50 mm) • Plumbing drains is 6" (150 mm)
• Other heat sources (baseboard heaters, fireplaces, forced air heating ducts, etc.) is 8" (200 mm)
Extending the heating cable cold lead
The cold lead is made up of two 14 AWG conductors with a copper braided shield, that is used as the grounding conductor. The extension must be made with building wire that is suitable
for this application and complies with applicable building and electrical codes. The cold lead itself is not made of building wire and therefore cannot pass through studs unless run through a
conduit. Extension of the cold lead requires the addition of a “code compliant” junction box that must be accessible at all times. The maximum length for extending the cold lead is 75 ft (23 m).
Extending the floor temperature sensor
The floor temperature sensor can be extended using an 18 AWG, 2-wire cable. The sensor wire itself is not made of building wire and therefore cannot pass through studs unless run through
a conduit. We recommend twisting and soldering the wires and using electrical tape to insulate them. There is no maximum length that is recommended, however the longer the extension the
greater the possibility that the quality of the signal (and resulting temperature sensing) will be skewed. Regardless of the method used, the resulting splice must comply with applicable building
and electrical codes. A loose connection between the extension and the sensor will result in a false reading or an error code.