Successful Underfloor Heating Installation from Devex

If you would like to undertake a successful underfloor heating installation, here are 9 tips;

- Check floor heights with the builder and ensure heating cables and their installation method are appropriate. There are various methods of floor construction, and the correct installation method differs for each type of heating cable. Note that heating cables are usually only suitable for specific floor constructions.

Before purchasing heating cable, make sure it is suitable for your floor construction, and review this with your builder before proceeding with the installation.

- Advise clients that thermal insulation is always recommended to ensure effective heating, lower energy consumption, and faster heat up.

Thermal insulation reduces heat losses wasted outside the area needing to be heated. It is always recommended to ensure that the heating cables are suitably installed to enable them to warm the floor to an acceptable comfort level. Without thermal insulation the floor is likely to take longer to heat up and cost more to run. If the heat losses are high, then the floor may not be able to achieve the occupant's preferred comfort heating level.

- Install each sensor in a separate conduit - not with the power cables.

Sensor cables must not be run in the same conduit as the power cables and each sensor must have its own conduit into the floor. The sensor is an electronic device which can fail if subjected to power surges, interference or nearby lightning strikes. If this should happen then it will need to be replaced and swapping sensors can rarely be done successfully if other cables are in the same conduit. - Connect Continuity Tester to installed Devimats until tiling is completed.

Continuity test alarms emit an audible signal if a Devimat cable is damaged significantly during the installation process. The alarm must be connected correctly and have a good battery fitted so that it can provide an immediate alert that damage has occurred, so that the location of the damage can be immediately identified for repair. It also serves to advise that more care is required to avoid further damage. An electrician should also check the cable resistance and insulation resistance prior to tiling because the alarm will only detect major heating cable damage, while otherwise undetected minor damage could lead to a future failure of the heating system. All heating cables need to be checked by an electrician prior to embedding.

- Always take photos of the entire completed installation and keep them on file.

Underfloor heating systems are only visible during the installation process, so taking pictures is highly recommended as proof that the work was carried out correctly. If there is a performance issue later, then there is a chance that the cause can be found in one of the pictures; also, the builder will tend to be more careful during subsequent works when he knows that a photographic record was taken. - Test the cable and photograph the ohm results shown on the multimeter and insulation resistance tester.

A properly installed underfloor heating system is characterized by specific electrical resistance and insulation resistance values, and any significant deviation indicates a problem that needs to be investigated before proceeding. These test results should be measured for comparison with those specified by the manufacturer, and pictures of the readings should be taken for documentation purposes - they can serve for comparison if performance issues arise.

- Have the builder sign-off a handover acceptance sheet to state that the cables have been installed in the correct areas and are in perfect operational condition.

A signed acceptance sheet is a document that can also be used. It ensures appropriate accountability when in conjunction with recording of the installation work and photographed meter readings. The simple fact of signing the acceptance sheet encourages the builder to be more cautious when carrying out subsequent work knowing that it will be their responsibility.

- Label the switchboard to show that heating has been installed, where it is installed and who to contact - 'dial before you dig'

Properly identifying circuits is part of good practice in electrical installations because it simplifies operation and maintenance. As heating systems have a slower response time than most other electrical equipment, it is not always easy to identify their respective circuit breakers by trial and error. Labelling is of great help when troubleshooting, for personal safety, and in the event that subsequent fitting or building works need to be done.

Displaying the contact information on the switchboard ensures that maintenance personnel can get in touch with technical support before carrying out other work or attempting to solve problems with limited information.

- Re-test the cable continuity ohms and insulation resistance when installing the thermostats

Testing the cable again before or when installing thermostats is always recommended because it helps identify potential problems. If this step is omitted, it may make it difficult to determine the cause of a subsequent performance issues. It is important to have evidence of the installation after the cables have been embedded.

You can always contact Devex Systems for advice if you are unsure or have any concerns regarding the cable selection or installation. Our web site also has many articles and helps that are available online 24-hours.