Installation Guide

22 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 36). 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
from the base of the wall to the thermostat electrical
box. Floor temperature sensors need to be threaded
through the same conduit containing the cold lead, or
within a separate conduit.
Thermostat to Power Module Connection
The signal wire used to connect the DITRA-HEAT-E
thermostats with DITRA-HEAT-E-RR power modules
must be 300 volt rated and does not need to be in a
conduit, if it has a proper flame rating (e.g., CM, CMG,
CMR, CMP, CL2, CL3, CL2R, CL3R, CL2P, CL3P, FT1,
FT4, or FT6).
2
3
Embed the heating cables between studs, at a spacing
determined in the Planning section on page 19.
A repeating 2 stud or narrower spacing shall not be used
as it may cause overheating and cable malfunction.
Exception: A two-stud spacing is used when connecting
a 240 V cable to a 208 V power supply. See page 33
for more information.
A wider spacing (e.g., 4 studs) will not provide sufficient
power to warm the floor to the desired temperature.
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
Two sensors must be installed in the floor assembly. We recommend installing each of the thermostat sensors at a different
location on the floor, evenly spaced between two cable runs, and ideally towards the middle of the heating cable layout.
However, a minimum of 12" (305 mm) into the cable layout is recommended to obtain satisfactory temperature readings.
When continuously alternating 3-2 stud spacing is used, install the thermostat sensors in the middle of a 3 stud cable spacing
section when flooring material is ceramic, porcelain or stone tiles. When AFC's (see AFC section on page 17) are used, install
temperature sensors in the middle of a 2 stud cable spacing section. 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 36).
7
Mark where the cold/hot splice will be placed, cut the
DITRA-HEAT or DITRA-HEAT-DUO matting and subfloor
(if needed to accommodate the thickness of the splice),
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 sensors.
• Heating cables may not touch, cross over, or overlap one another or itself.
• Minimum spacing from:
• Walls, partitions, and fixed cabinets is 2" (50 mm) • Forced air heating vents is 4" (100 mm) • Centerline of toilet drain is 7" (180 mm)
• Drain pipe is 4" (100 mm). For the linear drain, the cable must be 4" (100 mm) from the actual drain pipe and a minimum of 1" (25 mm) from the channel body edges.
• Other heating sources (baseboard heaters and other fixed heating devices, fireplaces, 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.