Electric Underfloor heating is extremely useful in providing comfortable heating in our homes. It is often utilised in bathrooms, be they the main bathroom or en-suite, electric underfloor heating can provide excellent heating without taking up valuable wall space. Though inherently reliable and simple in design with minimal moving parts, problems and failures can occur like all installations. This article deals with some of the problems that can lead to your electric underfloor heating system not working correctly and how you can successfully identify those problems or faults. How you rectify these faults depends on the nature of the individual fault.
Some faults are simple and require no specific skills to rectify. However, these tend to be centred around correctly setting the user controls and operation schedule with the systems time clock and setback functions. Other problems should only be approached if you have the competency for the task. Where the fault is electrical and you are not competent for the task, you should seek a professional electrician.
Whenever working or fault finding on electrical underfloor heating systems, isolate the electrical power to the system and verify it is safe before working on the system. When working on the system or carrying out repairs, always refer to the manufacturer’s instructions for your specific electric underfloor heating. If you’re asking yourself why is my electric underfloor heating not working, this article might be the answer you’re looking for.
Common Problems with Electric Underfloor Heating
There are several problems with electric underfloor heating that can occur, so it is worth being familiar with these and what the cause of them could be. However, there are only few points of failure with underfloor heating systems as they are designed for a long operating life. Therefore, it tends to utilise high-quality parts and components. This keeps the reliability of electric underfloor heating as high, if not higher, than other forms of heating. The problems that are most likely to occur can be broken down as follows:
- No heating, underfloor heating controller display blank
- No heating, underfloor heating controller display working
- Heating constantly on
Problem: No Heating: Underfloor Heating Controller Display Blank
If your problems with electric underfloor heating include no heat and a blank controller display, there are several checks that you should carry out to help diagnose the problem.
- Initially check that power is reaching the system.
- Next, ensure that the fuse or circuit breaker has tripped or blown for the underfloor heating circuit. Electric underfloor heating systems have an RCD (residual current device) breaker. This is usually located at the consumer unit, so make sure that this is in the on position.
- After that, check to see if other circuits supplied by the consumer unit have power to them. If more than one circuit is out, you may have issues unrelated to the underfloor heating. This can cause the circuit breakers to trip.
- Then, check locally to the underfloor heating controller for a fused spur that supplies power to the underfloor heating. Sometimes the manufacturer will have labelled these, but don’t count on it. Take a look at the integrity of the fuse. Although the fused spur will likely be 13 Amps, the fuse it contains may be of a lower rating. Always replace the fuse for one of the same rating.
- Finally, check wiring connections for security.
- However, you should check the wiring configuration if this is a new system, or a system not known to be previously working. Ensure that the correct wires terminate in the correct terminals. This is important especially on new systems as electrical installations aren’t uncommon. Isolate the system electrically at the consumer unit. Verify that you’ve disconnected the power before checking individual connections[i].
With these checks done, you should be able to establish power to the underfloor heating controller. If you have power but still have no display your underfloor heating controller may have internally failed and require replacement.
RCD’s are sensitive to moisture and unusual electrical loads[ii]. So, if the RCD keeps tripping it can indicate other issues that you will have to resolve for the system to function correctly.
The cost of this fault symptom to repair will vary. For example, a nuisance RCD trip which does not reoccur will likely cost nothing. However, a failed controller or a physical problem with the building may incur significant expenses, such as a manufacturer’s replacement part cost.
Problem: No Heating: Underfloor Heating Controller Display working Correctly
Check the settings of the thermostat by following the manufacturer’s instructions. The system must be set up correctly for the heating to work. Then, check that your controller’s thermostat is indicating a heating demand. If it is, but the controller is set up incorrectly, you can easily resolve this at no cost.
On the other hand, the issue may be a thermostat failure. If the wiring is correct and the thermostat has power, showing its symbol indicating heating demand but it isn’t producing heat, first check that the system is receiving power.
To find this out, isolate the power and check the electrical connections to the unit are secure. If everything looks in order, the thermostat may have failed. These controllers are inherently reliable, but failures can occur with all equipment that mechanically switches power.
As with other symptoms, it is worth checking the electrical connections for security. Also, ensure that it has the correct wiring layout.
Next, check the heating element’s resistance. If you have established that power is being directed by the underfloor heating controller to its load connections, isolate the power from the system, disconnect the heating element circuit from the controller and check its resistance with an ohmmeter. Open circuit readings can indicate physical damage or element failure. You should reference the obtained readings against the manufacturer’s data and, if significantly different, seek out further manufacturer assistance.
The cost of rectifying this symptom can vary. For example, a simple controller setting issue will cost very little. On the other hand, a new controller or wiring repairs can be expensive.
Problem: Underfloor Heating Constantly On
Check your underfloor heating controllers settings paying attention to the thermostat’s settings for demand. If this temperature is set too high, underfloor heating may not satisfy the need and continually heat the floor. This can occur with the timed off periods too, as most underfloor heating controllers provide a setback function where, rather than being completely off, the system provides heat when the temperature falls below a predetermined point set by the user. This means that the heating will turn on if the temperature falls below this setpoint and is not a fault.
Adjusting the setback setpoint lower will reduce the occurrence of this. It will also allow the room temperature to fall to a lower point before heating is provided, lessening the protection against low temperatures.
When electric underfloor heating fails to shut off, it can indicate a faulty Underfloor heating controller. The underfloor heating controller’s job is to switch power on the heating element when required. This means the controller is switching the full heating electrical load and this can cause the electrical contacts in the relay within to become welded closed. When the temperature is right, the controller will remove the demand for heating. Still, the relay will remain welded shut and supply power to the heating element. If this happens, it is important to turn off the electric underfloor heating and if possible remove the fuse from the fused spur supplying the system.
Before replacing a controller that has failed in this way, it is important to verify the resistance and amperage drawn by the underfloor heating element to ensure it is within the amperage capability of the controller. If you have any doubt, you should seek out the manufacturer’s assistance. Again, it can save hours of needless fault finding to verify a correct wiring layout and secure wire connections.
Again, the cost can vary. A simple change to the setback temperature or a non-existent fault will cost nothing. A replacement controller’s costs will depend on the manufacturer’s replacement parts pricing and any additional work, such as replacing wiring where resistance readings are either too low or open circuit.
Solve Your Problems With Electric Underfloor Heating
That covers the common answers to: ‘Why is my electric underfloor heating not working?’ However, many electric underfloor heating systems last their intended lifetime and experience no problems or breakdowns. But, now you know what to look out for should you experience any problems with electric underfloor heating. Also, should anything go wrong, you’ll know how to rectify the faults most often encountered with electric underfloor heating systems.
It stands to reason that if you’ve had high quality electric underfloor heating installed, you want it to work reliably and safely. If you find that your heated flooring isn’t working as expected, then it is essential that you seek advice or look to get this repaired as soon as possible.
Sources
[i] https://www.findtheneedle.co.uk/companies/ambient-electrical-ltd/news/floor-heating-not-working-no-display-on-thermostat
[ii] https://www.cambridgediscountelectrical.com/2019/12/12/what-is-rcd-protection/
