How to Retrofit Low Profile Wet Underfloor Heating

SCOPE OF SUPPLY FLEXIRO UNDERFLOOR HEATING KIT WITH CLIP RAILS

Please refer to the PDF installation guide for the kit components. You will also find further accessories and suitable tools in the FLEXIRO Shop.

NOTE:

As a general rule, the following also applies to FLEXIRO low profile underfloor heating: Work on heating systems requires sufficient technical knowledge and skills. If necessary, have the installation carried out by a specialist.

IMPORTANT INFORMATION BEFORE STARTING THE INSTALLATION

Determine the arrangement of the heating circuits. The installation position of the RTL-Box should be chosen so that the heating pipes from all heating circuits can be routed directly to the box without extending the heating pipes.

Note: Kit 2.5 m² = 1 heating circuit; 5.0 m² = 2 heating circuits; Kit 7.5 m² = 3 heating circuits and 10.0 m² = 4 heating circuits.

The pipes of the underfloor heating can be shortened. However, it must be ensured that the differences in length between the individual connections do not exceed 15%.

IMPORTANT INFORMATION BEFORE STARTING THE INSTALLATION

Avoid crossing pipes in order to take full advantage of the low construction height of thin underfloor heating.

Always make sure that the pipe is cut straight and burr-free. The pipe must not be squashed or kinked.

The installation of distributors and pipes does not require any special tools.

PREPARING THE INSTALLATION

The existing substrate must be level, clean, dry and load-bearing. Any primers can already be applied.

Before laying the pipes, determine the position of the connection manifolds for the underfloor heating so that you know exactly where you need to lead the pipes.

The arrangement of the heating system and the positioning of the RTL-Box can be designed individually. Please ensure that the control valve can be accessed later. It must be possible to insert the pipe ends into the individual connections after assembling the manifolds.

INSTALLING THE RTL-BOX

In order to provide efficient temperature control, the RTL-Box should be positioned in such a way that the thermostatic head can detect the temperature of the indoor air and the air can flow around it unhindered.

The installation and operating instructions enclosed with the UFH kit must be observed.

APPLYING EDGE INSULATION STRIPS

Gap-free edge insulation strips should be applied to all walls or vertical components (stairs, columns, door frames, ascending pipes). These must always reach the upper edge of the top covering.

The edge insulation strips are cut off once the top covering has been completely laid (or, in the case of tiles, once the tiles have been grouted).

EDGE INSULATION STRIPS

Edge insulation strip after being installed

FITTING THE CLIP RAILS

The clip rails are fixed directly to the floor. This can be done, with screws and dowels, knock-in dowels or building adhesives.

Before installation, the planned heating area should be marked out on the floor.

FITTING THE CLIP RAILS

When installing the clip rails, make sure that they are adequately fastened. It should no longer be possible to move them in a horizontal or vertical direction after they have been installed.

The clip rails should lie flat on the floor to ensure that the pipes are securely fixed.

LAYING THE UNDERFLOOR HEATING

When laying the underfloor heating, all distances specified in the installation drawing must be observed. The clip rails are fixed at 40 - 50 cm intervals, and at 10 - 25 cm intervals in areas where the pipe bends.

LAYING THE HEATING PIPES

The optimum starting point for laying the pipes is near the distributor arms in order to keep the pipe length for the connection as short as possible.

Various installation patterns for laying out the pipes are possible, e.g. meander- or snail-shaped installations.

LAYING THE HEATING PIPES

The minimum spacing between the pipes is 10 cm. The distance between the underfloor heating and the perimeter walls should be at least 5 cm. A minimum bending radius of 8 cm must always be maintained in areas where the pipe bends.

LAYING THE HEATING PIPES

Cut out any kinks or damaged areas on the heating pipe. After that the pipe must be reconnected with a permanently tight coupling (plug-in connector). The coupling must be protected from direct contact with the casting compound by wrapping it in PE film. The position of the coupling should be marked. After this repair the pipes may have to be extended.

LAYING THE HEATING PIPES

The 10 mm PE-RT pipe is pressed into the clip rails

LAYING THE HEATING PIPE

Meander-shaped laying of the underfloor heating system

LAYING THE HEATING PIPE

The pipes should be laid without any twisting. The pipe overhang in the bend area should be approx. 10 - 25 cm. The loops can be fixed with dowel hooks.

CONNECTING TO THE RTL-BOX

The distributor arms are connected to the RTL-Box with a Eurocone screw connection. The Eurocone has a self-sealing effect while the metal screw connection has a purely safety-related function. Over-tightening should be avoided as this would compromise the safety of the heating system.

CONNECTING TO THE RTL-BOX

The arrangement of the heating pipes in the RTL-Box is shown here. The heating pipes are connected to the distributor arms by means of a simple plug-in assembly. The heating pipes that have just been cut and possibly shortened are inserted directly into the plug-in connections of the distributor arms up to the stop.

CONNECTING TO THE EXISTING HEATING SYSTEM

As a rule, you can either integrate your FLEXIRO underfloor heating into the existing heating system parallel to existing radiators or instead of a radiator.

Make sure that the supply and return lines are correctly connected in the RTL-Box. Mixing up the supply and return lines in the Box will disable the thermostatic valve and even prevent the flow through the FLEXIRO underfloor heating system.

CONNECTING THE RTL-BOX TO THE EXISTING HEATING SYSTEM

Laying the connection hoses from the rtl-Box to the heating system

PRESSURE TESTING THE HEATING SYSTEM

Make sure that the system and all associated components are correctly installed before putting the wet underfloor heating system into operation.

Take into account our detailed instructions for the pressure test in the PDF installation guide.

TESTING THE UNDERFLOOR HEATING

Be sure to carry out a trial run before embedding the pipe system. This is the last chance to correct installation errors or repair damage:

APPLYING THE FLOOR SURFACE

The underfloor heating must be switched off when applying the levelling compound!

The minimum construction height is 12 mm if a ceramic floor surface is chosen. With other floor surfaces, the self-levelling compound should provide an additional covering of at least 5 mm above the heating pipe. All floor coverings must be rated "suitable for underfloor heating".

COMMISSIONING (HEATING UP PROCESS)

After complete installation of the underfloor heating and once the surface covering has naturally dried, the heating up process takes place. If you have laid tiles, do not operate the underfloor heating until the tile adhesive has completely hardened. Please follow the manufacturer’s application instructions.

Heating-up is usually carried out according to a heating-up protocol. It is essential that you follow the manufacturer's instructions.

HOW TO FIT A LOW PROFILE UNDERFLOOR HEATING - LAYING PLAN

Low profile water-based underfloor heating with clip rails, laying pattern: meander-shaped

HOW TO FIT A LOW PROFILE UNDERFLOOR HEATING - LAYING PLAN

Low profile water-based underfloor heating with clip rails, laying pattern: bifilar