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Vysa-Cable 18W In-Screed Underfloor Heating Kit

  • Ideal for new-builds, refurbishments and extensions, especially conservatories
  • Designed to be covered by 50-75mm sand and cement screed
  • Can be installed in a bathroom or shower room
  • Kits provide flexible solution with thermostat, fixing strips, strong tape and cable

Vysa-Cable 18W In-Screed Underfloor Heating Kit

Vysa-Cable 18W In-Screed Underfloor Heating Kit

The in-screed cable is rated at 18W per metre and depending upon how it is spaced when being installed, you can achieve ratings of 125, 140 or 160W/m2.

The last is ideal for primary heating in high heat loss areas (such as conservatories), but well insulated dwellings can often be heated using 140w/m2 and for secondary heating 125W/m2 is usually all that’s needed.

The Vysa-Cable is approved to IEC 60800.

See order codes for a table showing coverage at different ratings.

Vysa-Cable 18W In-Screed Underfloor Heating Kit

The kit includes:

  • Vysa-Therm 3000 fully programmable thermostat (can be upgraded to a Touch Screen model on request and by extra payment)
  • Vysa-Cable 18W/linear m 2-core heating cable
  • Screed Fix Galvanised steel cable fixing strip
  • Mi-Ti strong self-adhesive tape for Screed Fix
  • Floor temperature measurement sensor
  • Flexible conduit for floor sensor
  • Full Installation Instructions


What to do:

Choose the kit that suits the application
•Prepare the sub-floor
•Plan the cable runs and site the thermostat
•Secure Screed Fix fixing strip
•Lay the heating cable at the correct spacing
•Secure the heating cable to the Screed Fix
•Run the cold tail cable through conduit to the thermostat
•Install the floor sensor and run the conduit to the thermostat
•Get an electrician (Part P qualified) to connect up to the mains

Vysa-Cable 18W In-Screed Underfloor Heating Kit

Order code cable ONLY Order code in-screed cable kits Cable Length (m) Nom. 125W/m2 cable spacing 15cm = room area m2 Nom. 140W/m2 cable spacing 12cm = room area m2 Nom. 160W/m2 cable spacing 11cm = room area m2 Total Wattage
2534 SK160 8.5 1.3 1.1 1.0 160
2535 SK260 14.5 2.0 1.8 1.6 260
2536 SK320 18.5 2.5 2.2 2.0 320
2537 SK420 24.0 3.3 3.0 2.6 420
2538 SK520 28.4 4.1 3.7 3.2 520
2539 SK600 34.4 4.8 4.2 3.7 600
2540 SK740 41.8 5.9 5.2 4.6 740
2541 SK830 46.1 6.6 5.9 5.1 830
2542 SK1000 57.5 8.0 7.1 6.2 1000
2543 SK1200 68.9 9.6 8.5 7.5 1200
2544 SK1500 83.2 12.0 10.7 9.3 1500
2545 SK1700 100.4 13.6 12.1 10.6 1700
2546 SK2200 122.7 17.6 15.7 13.7 2200
2547 SK2600 149.6 20.8 18.5 16.2 2600

Before commencing the entire sub-floor should be swept clean and free from any sharp objects. If laying onto foil backed insulation ensure the area is dust free to enable a good fix.

It is good practice to plan your installation using a sketch marking your laying pattern and planning the positions for the floor sensor, the connection box and thermostat.

Attach the Screed-Fix band to the sub-floor or insulation using fixing nails or the Mi-Ti high impact adhesive tape. The Screed-Fix bands should be spread evenly across the floor at intervals of 750mm. A 75mm border should be left around the perimeter of the room. Do not remove the cable from the drum before laying as it will twist an make the installation difficult.

The heating cables (black cables) must not touch each other and should never cross. The heating cable must not be cut or shortened and the joint between the cold tail and the heating cable must not be bent or put under strain.

The floor sensor for the thermostat should be positioned between 2 heating cables approximately 500mm from the wall. The black flexible conduit provided should always be used to install the floor sensor probe. Once laid the heating cable should be covered with a minimum of 50mm sand and cement screed.

Before and after covering the heating cable with the screed, the cable resistance should be checked against the label value. Avoid traffic over the areas until the cable is completely protected. The screed should be allowed to dry completely before turning on the system. Please check screed manufacturers instructions.

A fully qualified electrician must now make the final connections to the mains supply and install the thermostat. The thermostat should be installed in the room to be heated. For bathrooms the thermostat must be placed outside Zones 1 & 2. Finally the electrician should check for continuity of the floor sensor and retest the resistance of the cable. A further insulation test should be carried out in accordance with IEE regulations.


The installation should be protected by a 30mA RCD for safe operation.