Underfloor heating problems and how to solve them

UFH technical support


Underfloor heating users worldwide experience the many benefits and comforts of a home heated in an even, efficient and comfortable fashion.

Underfloor heating systems require very little attention and maintenance but that does not mean that they are immune to problems. Some problems may only cause small, minor issues that make the system less effective but in worst-case scenarios, the problem can prevent the UFH from working completely.

As UFH is a covered system, the idea of a repair can be daunting for homeowners. However, past the installation of the floor coverings, it is not necessary to access the covered pipework. Find out the common problems that occur with underfloor heating below and how to fix them.


Air in the loops

UFH systems work by circulating warm water through a series of continuous loops that are fitted underneath the floor to create a large surface that heats a room from the floor upwards. Foreign objects or anything caught in a loop can cause blockages and reduced flow, reducing the heat output of the system.

The main cause of air in pipes is when pockets of air are trapped by the flowing water. The air in the pipes is unlikely to develop into a major issue, but it can reduce the heat impact of a system and result in patches of the floor which aren’t as warm as the rest.

Once this problem has been identified, the best solution is often to bleed the underfloor heating system.


Before you begin

  • Check the pressure in the system. Rising and falling pressure means your system is ok. If the pressure is low, it could mean there are underlying issues with a heating system.
  • Add water to the system and keep an eye on any adjustments.
  • Check and release the air bleed valves. This helps you to determine if there is air trapped inside.


Solving the problem

  • Once UFH is full of water, bleed the ports. Wait for ten minutes after the system is filled before venting ports as it prevents air from getting back into the system.
  • Start venting the underfloor heating system. Start with the lower side of a property then move to pipes on the upper side.
  • Vent each valve one after another. Only ever individually.
  • Make sure you have a towel or cloth as water is likely to appear.
  • Drain off the waste.
  • Close each valve once you’re done and flush out the pipes to refill the system.
  • Repeat until every valve is done.


After you’re done

  • Check the pressure level again. It may rise after venting.
  • If the pressure is too high or too low, further repairs may still be necessary.


UFH installer


Actuator Problems

An actuator is a component of a machine that moves and controls a mechanism or system e.g. opening a valve. When it comes to UFH, issues with actuators usually occur due to poor connection or sticky pins.


Actuator failure

An actuator needs an electric charge to work. If there is a wiring problem between the system or the thermostat then an actuator can’t function. Electricians will need to check the circuits and assess.


Sticky pins

Beneath every actuator, there is a pin. If the pin is stuck then the actuator doesn’t release properly – meaning that the system may be on when it’s not meant to be, or not on when it is meant to be. Use silicone spray and a pair of pliers to free the pin.


Heat displacement 

Homeowners may notice that certain parts of their UFH don’t feel like they’re releasing heat the way they are supposed to. This problem is often linked to circuits or actuator placement as a result of poor labelling at the installation stage.


If hot water is not flowing to the zone: 

  • Check the electrics, flow rates and flow temperatures as detailed above.
  • The zone actuator heads may be fitted to the wrong zones.


Checking connections are correct: 

  • Turn all room thermostats down to 5 ̊C
  • Check zones individually (other zones must be off)
  • Turn the thermostat in the zone up high
  • If another zone gets warm, it shows the actuator controlled by the thermostat is probably fitted to the wrong zone valve
  • Continue to test all other zones and move actuators to their correct positions
  • Re-label actuator heads


ufh pipework


Floor heating stays on all the time

If a UFH system is running constantly then it can probably be contributed to the underfloor heating thermostat controlling it.


Thermostat Settings

Check the settings to ensure the floor heating is not being powered. If it’s even on low when not needed, the thermostat can be calling for heat.


Faulty Thermostat

Thermostats can get stuck in the on position. The electrical contacts stay closed regardless of the thermostat settings or temperature reached and will continue to power the floor.


Incorrect Wiring

Make sure that the wiring on the back of the thermostat has been connected as per instructions.


Poor installation

If an installer has been careless during UFH installation or the proposed plans were not closely followed, it can create problems further down the line. Although there are lots of ways installers can jeopardize laying the pipework, such as create too tight of a bend in the pipe that reduces the flow rate, one of the most common incidents is damage to the pipes during installation

If the original installer has used a knife to cut material close to pipework then they may have caught the UFH pipe. If a pressure test isn’t properly carried out that indicates this breach in the pipe network or the hole begins to grow, leaks beneath the floor will occur. This will result in some very intrusive investigations if the floor covering is already down, and the house occupied.

First, identify that it is a UFH pipe by pressure testing each zone separately. Once you’ve isolated the leak, you’ll need to get to the pipe. If it’s just a hole you can cut off the damaged pipe and refit a new piece with a coupler.


UFH systems


Avoiding common UFH issues



Sometimes oversight is accidental. Sometimes it occurs as a result of neglect or poor training. If tests aren’t run to check the efficiency of the system during and after installation then there’s a threat that a problem will go unrecognised and develop later.

Ambiente provides underfloor heating certificates for installers to fill out. These work as a reminder for installers but also as valid documentation that the checks have been carried out.


Correct specification

Having the correct underfloor heating for the requirements of a residential or commercial building makes sure that home and property owners are maximising the efficiency of their UFH.

Whether it’s for retrofit or new builds, suspended floors or a bespoke system, having the correct underfloor heating specified prevents poor heat return and dissatisfaction.

At Ambiente, we’re always developing new products to raise the bar in the UFH market and we’re sure we can provide the best fit to meet requirements.



As UFH problems can be very stressful and time-consuming, trusting the products that make up an underfloor system is important for the end client and the installer who should only want to work with high-quality equipment.

Ambiente are so confident about the quality of our pipework that we will provide compensation on top of the above-mentioned warranty up to a maximum amount of £3million per individual case up to an aggregate limit of £9million of damage if the material damage and any subsequent connected damage has been caused by us due to the use of defective Ambiente piping.

Fixing underfloor heating systems can be a difficult task. That’s why it’s so important to make sure that UFH is installed to all specifications and artwork during the primary stages. Ambiente’s technical resources and installer accreditation provides the foundations of information needed to get the job done properly, making sure rare problems are stopped early.


UFH resources


Become an Ambiente accredited installer and gain access to information that can improve your technical knowledge and project leads. Just contact Ambiente on 01707 649 118 or email info@ambienteufh.co.uk


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