Common Underfloor Heating Problems and Simple Ways to Fix Them

Underfloor heating kits are the easiest and most economical way to heat your home.  By choosing underfloor heating, you are adding value to your house, helping the environment, and ensuring an even heat throughout the space.  

The most significant concern raised by potential customers is the inconvenience that could be caused should the underfloor heating require maintenance.  This guide is intended to solve some of the most common problems and demonstrate that servicing your new heating system should prove simple.

A solution to a single zone of the underfloor heating system is not heating up

You have identified that one area of your home never heats up.  This is simple to spot, as the floor will be cold underfoot.  One of the benefits of underfloor heating is it is usually easy to locate when you need a service of some kind, and where.  The potential causes of such a problem include:

Underfloor Heating Valve Actuator Problems: it could be that there is a sticky pin valve underneath an actuator.  The actuator is the mechanism that causes a device to operate.  The solution requires removal of this actuator from the affected zone and a check to see that the pin valve is free.  You can use a silicone spray or a long pair of pliers to free the pin if it is stuck down.

If the actuator has failed, it is likely that there is an electrical issue.  This issue requires you to contact an electrical engineer who will want to check your thermostat or your wiring board.  This is also a common cause for the heating to be stuck on, as well as stuck off.

Thermostat issues: If your heating is not coming on in a single area then there could be a problem with the settings in the thermostat.  It is a good idea to check the batteries first, then to check the user-guide, to make sure you have the settings correct.  When you have checked all the apparent potential causes, and you still have no joy, you will need the help of an electrical engineer.

You will know if it is a thermostat setting error because the thermostat will display an error message, either E1 or E2.  Using the user guide, reset the thermostat, and this should clear the error.

Air in the system: Like with radiators, air can get trapped in the underfloor heating loop.  The means of removing the air sounds, but it is as simple as pushing any blockage through a pipe. First, you need to isolate all zones except the one that is not heating up.  Remove the actuator and connect a hosepipe to the flow valve.  You should then connect the hose pipe to a cold tap.  Connect another hose to the drain off point on the manifold and take out waste. Only when both pipes are connected, switch on the cold tap and flush the water through the system. 

This is a lot easier than you may think, but it may be best to ask a plumber to carry out the task, to ensure pipes are connected to the correct manifolds.

Wiring issue: There could be a faulty connection.  The connection could be within the actuator, the thermostat or the wiring board.  This is an electrical issue, and an electrician will be able to resolve this quickly.

Solutions to multiple zones or the entire heating system are failing to heat up

Is your underfloor heating not heating up at all? You have noticed that more than one zone or even the whole system has stopped heating up.  This indicates a more significant problem with the system, and you will likely need a plumber or electrician.  However, the technician should be able to resolve the issue without too much inconvenience.

Failure of the circulation pump/ pump relay or wiring board: these are electrical issues, and you should seek the help of an electrician.

Isolation valves closed on the manifold: this is easy to check.  The isolation valve should be in line with the pipes on the manifold if it isn’t then it is stuck in the closed position – this is easy to see, as it will be at 90 degrees to the pipe.  This should take a matter of moments for a qualified technician to resolve.

Blending valve pin stuck: as with the stuck pin in the actuator, this can be resolved with silicon spray or a long pair of pliers.  You merely need to unstick the pin.

Boiler issues/ no power on the wiring boards: there could be a problem with signals getting to the boiler, which will require the help of an electrician.  It could be that the boiler isn’t working at all.  As with a central heating system with radiators, this is easy to check as there should be a flame alight in the boiler.

Solution Three: The underfloor heating pump is working constantly

You will become used to the sound of the pump firing on and off, as you would expect a boiler to switch on when the thermostat demands more heat.  Therefore, it is easy to spot when this pump is running all the time and is a clear indication of a problem.  You are likely getting heat, but you are also using a lot of electricity, so it is a good idea to resolve this problem quickly.

Pump relay stuck on wiring board/ faulty thermostat/ underfloor heating actuator problem: all these issues are a result of electrical problems that will require the assistance of an electrician.  You could try resetting the thermostat, clearing potential errors, before making the call for a technician.

A Solution to Pressure Problems

It is possible to get a rise in pressure in the system, as well as a loss of pressure.  There are a few potential problems that are relatively easy to identify.

Filling loop left on: you can resolve this efficiently by checking that the valves at either end of the flexible hose are in the closed position and that you have disconnected the filling loop.

Restriction in the pipework: there could be debris in the pipework, or air trapped in the pipe somewhere.  You can check this quickly by switching off the pump, and if the pressure varies, then it is likely a blockage of some kind.  Follow instructions for flushing through the pipes but note this is best done by a plumber.  It is also important to note that your pump is close to the valve then there will always likely be a rise in pressure when the pump starts up.

Diaphragm damaged: it is possible that the whole expansion vessel will need to be replaced if the diaphragm has been ruptured.  An engineer can test this by depressing the needle in the Schrader valve on the underside of the expansion valve.

It is also possible that the diaphragm may be empty of air, so there is no room for water to expand as it heats.  An engineer will use a foot pump to relieve some of the water pressure, which should efficiently resolve this issue.

Falling pressure: leaks in the system can cause a loss of pressure.  You should be able to identify where there is a leak by re-pressurising different zones of the system one at a time.  It could also be an issue with the pressure relief valve, the expansion vessel on the boiler or the boiler blow off valve.  It is a good idea to seek support from an electrician for issues with the boiler and a plumber for problems with valves and pipes.

Can Underfloor Heating Problems Affect the Functionality of Radiators When Used Together?

Even though each of these solutions advises you seek the advice of a plumber or electrician, none of these solutions requires significant construction work to replace your heating – which is usually the main concern of most people considering underfloor heating.  Underfloor heating is a reliable system, and it is unlikely you will experience problems regularly.  When problems do occur, our technicians often report that it is something simple and easily rectified.

If you want to ensure your heating works, then you can invest in a service plan.  It is possible that your service provider could then visit regularly to flush out the pipes to remove sludge build-up and therefore stop a blockage before it interrupts your comfort.  They will also check your valves and manifolds, ensuring that all are in the correct position and free to move, preventing stuck pins and damaged seals.  As with any heating system, you should have your boiler regularly serviced.

You can now invest in your underfloor heating system knowing that if there is a problem, there is a quick and straightforward solution.  However, what is maybe more important to know is that most architects choose underfloor heating systems because they are so reliable and once installed are unlikely to need servicing and maintenance.