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Thermostat Temperature Controller

The thermostat should be positioned (fig.1) at a height approximately 1.5m from the floor, in an area free from draughts, out of direct sunlight and close to the electrical supply.

All thermostats have a floor sensor, which is placed in a protective plastic conduit and positioned centrally below one of the heating elements at a distance of approximately 0.5m from the wall. A single gang flush fitting minimum 25mm deep back-box (45mm preferred) will be required for the thermostat.

Junction Box Installation

A junction box (fig.1, preferably 2 gang x minimum 25mm deep) is required for commoning up the Carbonwarm® heating element 5m long connection leads. This should be sited close to the thermostat and in a position to enable all the connection leads and the temperature controller sensor conduit to reach the box comfortably.

Floor Sensor Installation

Cut a 13mm wide by 6-7mm deep channel in the subfloor (fig.2) to accommodate the sensor conduit so that top of the conduit will be level with the Fastwarm®-Lite thermal insulation surface when installed (see fig. 2). Tape over the end of the conduit using a small piece of Fastwarm® fixing tape. Place the conduit in the channel and feed the end into the junction box. The conduit can now be cut to length leaving approximately 5cm inside the junction box. Slide the sensor into the conduit until the sensor bulb reaches the taped end. Wrap a piece of tape around the conduit and sensor cable to prevent the sensor being accidentally pulled out. Use Fastwarm® fixing tape to hold the conduit in place in the channel.

Laying Fastwarm®-Lite Thermal Insulation

Thoroughly clean the existing floor area taking care to remove any sharp objects.

Lay the Fastwarm®-Lite roll as illustrated in the drawing (fig.3). Always remember to cover the total floor area with Fastwarm®-Lite, even unheated areas. Tape along the edges using Fastwarm® fixing tape - 25m² of Fastwarm®-Lite will require approximately 50 metres (1 reel) of Fastwarm® fixing tape.

Carefully cut a channel in the Fastwarm®-Lite at the position of the sensor conduit channel using a sharp knife and straight edge. Tape over the conduit using Fastwarm® fixing tape.

Laying Carbonwarm® Heating Elements

Working from one side of the room, roll out the first element copper side down, with the connection leads closest to the thermostat wall, leaving a minimum 50mm gap from walls. Apply light finger pressure on the cable connection covers to leave an imprint on the Fastwarm®-Lite, move the element to avoid damage and using a sharp knife remove the Fastwarm®-Lite to allow the cable connection cover to sit flush with the Fastwarm®-Lite surface (fig.4).

Before commencing, check the labels on each of the Carbonwarm® elements to ensure they are the correct sizes.

Adjusting Carbonwarm® Heating Elements

Carbonwarm® heating elements are available in standard lengths from 2 metres to 10 metres in 1 metre increments. Should the elements require to be shortened, this can be easily done by cutting along the cutting line using either scissors or a sharp knife and straight edge; insulating the copper strips using the insulating green polyester tape discs (4 discs supplied with each heating element) as shown in the diagram (fig.5).

Care should be taken not to cut closer than 3mm from the edge of the black heated area. Repeat the procedure for the remaining elements, butting adjacent elements edge to edge.

Taping Carbonwarm® Heating Elements

Tape along the edges of the heating elements using the Fastwarm® fixing tape, taking care not to damage the heating elements - 25m² of heating element will require approximately 50 metres (1 reel) of Fastwarm® fixing tape.

Using a sharp knife: cut a channel in the Fastwarm®-Lite along the connection lead/thermostat wall side to accommodate the connection leads (fig.6). Run the leads in the channel to the junction box and tape over using Fastwarm® fixing tape.

Laying Carbonwarm® Polyester Vapour Barrier

The installed Carbonwarm® heating elements must be covered with the Carbonwarm® Polyester Vapour Barrier to provide optimum moisture and additional mechanical protection. Carbonwarm® Polyester Vapour Barrier is available in a 1m width, with 2 roll sizes of 5m² and 25m²: due to overlapping, a 10% allowance should be made to each roll to calculate the reduction in total coverage when installed (a 25m² roll will cover 20m²).

To install, roll out the vapour barrier, cut to length and overlap adjacent pieces by a minimum of 100mm (fig.7). Tape along the entire length of the overlap using Carbonwarm® fixing tape (1 x 25m² roll of vapour barrier will require approximately 25m of fixing tape).

Note: Always remember to cover the entire floor with the vapour barrier, even unheated areas.

Making The Electrical Connections

Carbonwarm® heating elements are connected together using the new lever action Carbonwarm® connector. A separate connector is used for the live and neutral connections. A single pair of connectors will connect 4 Carbonwarm® elements to the thermostat output (fig.9). To connect up to 7 elements, 2 pairs of connectors will be required with each pair being connected together using a suitable link wire - maximum 2.5mm2 solid or up to 4mm2 fine stranded cable (fig.9).

Carefully insert all brown and blue cables into separate commoning blocks as shown in the diagram (fig.8). A suitable cable (maximum 2.5mm² solid) will be required to connect the commoning blocks to the output of the temperature controller.

Please note: Carbonwarm® underfloor heating film is rated at 130W/m2 and operates on a standard 230 Volts mains electrical supply: a single 16-amp thermostat will control a maximum Carbonwarm® heated area of 28m².

Controlling A Carbonwarm® Heating System

If the installed load exceeds the temperature controller power rating of 3680 watts (16 amps) there are 2 options to control larger installations in excess of 3680 watts:

Option 1 - Divide the heated areas into separate zones controlled by individual thermostats, up to the maximum – as above.

Option 2 - A contactor is required to control your Carbonwarm® heating system with a single thermostat – see below

Contactors are used where a single thermostat is required to control a total area of underfloor heating exceeding 3680 watts or a total loading of 16 amps.

The Floor Heating contactor will control up to a maximum of 22,000 watts or 96 amps total loading – a total Carbonwarm® heated area of 169m2. For more information on the Floor Heating contactor click here.

Carbonwarm® underfloor heating systems must be protected by a 30mA RCD (residual current device) and a suitably rated fuse or MCB (miniature circuit breaker).

Electrical connections must be done by a qualified electrician and the complete installation must comply with BS 7671:2001 (IEE Wiring Regulations) and Part P of The Building Regulations.