Underfloor Heating Problems That Affect Your Business

In this article we will look at the most common problems you might encounter with your commercial underfloor heating system and what might be causing them.

Underfloor heating (UFH) systems are a low maintenance and cost-effective way to heat commercial buildings. While some UFH systems are electric, most commercial properties use water-based systems. They’re larger and more complex, but they can heat multiple rooms more effectively than traditional heating systems.

While underfloor heating systems are generally reliable, sometimes things go wrong. Poor installation or a lack of maintenance can lead to long-term problems. Faulty components, corrosion, and other issues can cause leaks, zones not heating up properly, and pressure issues.

Often, a singular issue can become several if not resolved quickly, and sometimes multiple issues are interconnected, requiring more complex repairs. As a part of Akehurst’s heating and plumbing services, we can install your system properly, provide planned maintenance, and repair issues before they get worse.

Single Zone Not Heating Up

If a single zone in your business’s underfloor heating system isn’t heating up, the cause is likely located after the manifold (the system’s central control unit). It might also be a problem with the manifold itself, like a damaged actuator or valve. Here are some of the possible causes, with more detail on each in the sections below:

Issues with thermostats
Actuator problems
Flow gauge issues
Pipework problems
Wiring problems

Possible Cause: Thermostat Problems

Each zone has its own thermostat to monitor its temperature. When a thermostat doesn’t take accurate temperature readings, it can’t signal to the manifold that the zone needs heating, and the actuators (gates that control water flow to each zone) won’t open.

If your thermostats rely on batteries, low battery power can cause inaccurate readings. Changing the battery can fix the issue, but the thermostat may calibrated incorrectly. Our commercial electricians can diagnose and fix problems with your thermostats quickly and reliably.

Possible Cause: Actuator Problems

Actuators are gates on the manifold’s valves that open and close in response to signals from the thermostats. Sometimes the actuators that control water flow to each zone might not be working properly.

If the problem has existed since the system’s installation or previous maintenance, the actuators might not be placed properly on their valves, preventing hot water from flowing to the correct zone.

The pin valve underneath the actuator might be stuck, preventing the gate from opening and closing properly.

Alternatively, the actuators sometimes fail because of electrical issues. We can inspect the manifold to identify and resolve any actuator-based problems.

Possible Cause: Flow Gauge Problem

Flow gauges measure water flow in the underfloor heating system. Accurate flow rate measurements are critical for controlling the system, as it affects how much water is distributed to each zone and therefore, how much each zone heats up.

Each zone has its own flow gauge, so malfunctions can cause single zones to not heat up properly. If the flow gauge is giving incorrect readings, the system may not send the right amount of hot water at the right intervals to maintain the zone’s heat. To fix this, the flow rate needs to be adjusted on the manifold.

Possible Cause: Pipework Problems

Problems with the pipework include air bubbles, leaks, and blockages. Air bubbles in the pipework (airlock) slow the water’s flow rate and can damage system components because of unexpected changes in temperature and pressure in the system. This is often because air can become a lot hotter than liquid water and put higher pressure on the system than it was designed for.

At Akehurst, we can run thermal imaging on your underfloor heating system to detect where air bubbles are slowing the flow of hot water, and flush water through the zone to remove them.

If there are leaks in the pipework, hot water that is supposed to be heating a zone will end up somewhere unexpected. Water leaks can cause problems with mould, damage to ceilings and floors, and make electrical components short circuit, among other things. Hot water leaks can also be found using thermal imaging to spot places where there is an unexpected amount of heat.

Blockages in the pipework impact the water flow. They can be caused by corrosion and debris collecting in the system. To remove this debris, the system needs to be flushed.

Possible Cause: Wiring Problems

If all the above components are working, a faulty wiring connection may be causing a zone to not heat up properly. Our commercial electricians are experienced with maintaining wiring for underfloor heating systems and can quickly detect and solve electrical issues.

Multiple Zones / Entire System Is Not Heating Up

When multiple zones aren’t heating up properly, or the entire system is running into issues, the problem is likely being caused by the manifold, or somewhere before it.

The manifold is the heart of the underfloor heating system. It directs the flow of hot water to each zone depending on the zone’s thermostats, flow rate, and other factors.

As the manifold splits the water flow into each zone, if all zones are affected by a problem, the root cause probably won’t be after this split. It’s still possible for multiple zones to have issues after the manifold, especially if the system hasn’t been properly maintained.

Some of the possible causes are:

Manifold problems
Issues with the pipework before the manifold
Boiler not firing
Wiring board failures

Possible Cause: Problems On The Manifold

Hot water from the boiler enters the manifold, then exits through many smaller pipes that each go to a different zone, much like how your arteries carry blood to different parts of the body. Valves and actuators open and close each line to let hot water through when it is needed and stop the flow when the zone is at the right temperature.

Problems with the manifold could be caused by a failed circulation pump, which continuously circulates hot water through the pipework. It could also be the pump relay failing, which means the circulation pump won’t be activated at the right time. These issues might be an electrical fault or damage to the component itself.

The manifold also has a lot of valves, including isolation valves that allow you to shut off specific zones, and blending valves that mix hot and cold water to reach the desired temperature. The valves might have stuck pins or other damage preventing them from working properly.

Possible Cause: Problems With Pipework Before Manifold

If air is trapped in the pipework before the manifold (airlock), it prevents water from flowing effectively from the boiler to the rest of the system. Many UFH systems are designed with bleed valves to remove air from the system.

Leaks and blockages in the pipes also disrupt water flow. Thermal imaging and pressure tests can also be used to identify leak locations before the manifold, while blockages are fixed by flushing the system.

Possible Cause: Boiler Not Firing

The boiler is responsible for heating the water. If it isn’t firing, there are two major causes: an electrical problem with the wiring board connections and relays, or a problem with system pressure. If the pressure is too low, the boiler may automatically refuse to fire to prevent system damage.

Possible Cause: Wiring Centre Not Working

Your underfloor heating system is controlled by many electrical components. A wiring centre typically houses all of the wiring for the boiler, actuators, and pumps. Issues with the wiring centre require an electrician to diagnose and fix.

Floor Isn’t Reaching Desired Temperature

If your floor isn’t heating up as much as it should, it might be because of faulty temperature sensors. A clear sign of this is when your boiler and manifold do not register similar temperatures,

It could also be poor insulation, the UFH system may not be able to produce enough heat to offset heat loss, this is particularly a problem for larger properties.

Alternatively, the water pressure may have failed. When the pressure is too low, hot water can’t be distributed effectively to heat up the floor, and the system might need to be bled to remove air bubbles.

Pressure Problems

At Akehurst, our plumbing contractors check pressure as part of UFH system maintenance to ensure that the pressure isn’t too high or too low. Problems with pressure can reduce system efficiency, cause damage, and even prevent it from working at all.

Pressure Too High

Pressure that is too high can damage pipework and components, and cause leaks. If the filling loop has been left on, water will continue to enter the heating system from the mains water source, increasing the pressure.

Blockages in the pipework can also cause increased pressure as water is forced through a narrower space. At Akehurst, we offer full pressure testing to check for these problems.

When the water pressure is too high, the expansion vessel can fail. The expansion vessel is a pressurised tank with water on one side and air on the other. Hot water takes up more space than cold water, so when the water in the system is heated it expands in the expansion vessel and the side with air compresses. If the membrane between the two sides breaks, there is nothing to facilitate this expansion.

Pressure Too Low

Water leaks will usually cause a drop in system pressure, killing system efficiency as well as making a mess. Beyond that, underfloor heating systems naturally lose pressure over time as air sneaks into the system. Too much air in the system can do more than just cause pressure loss, it can also damage pumps and lead to boiler lockouts.

Your underfloor heating system should be designed as airtight as possible, and have ways to remove air that does find a way in. Bleed valves are located on the manifold, and allow for air to be manually removed.

Regular maintenance can prevent problems that lead to an increase of air in the system, like leaks. We can also help install automated air bleed valves that remove air without needing someone to turn a valve.

Bills Have Suddenly Increased

An increase in your utility bills can indicate problems with your building’s insulation. If the building’s insulation isn’t good enough, heat produced by the underfloor heating system will escape.

On the other hand, some types of flooring, like hardwood and thick carpets, can prevent heat from being transferred from the UFH system to the target zone. This increases the demand on the system to reach the desired temperature, driving up your utility bill.

Increased bills aren’t always a problem with insulation, as airlock can also significantly reduce the efficiency of your UFH system and hike up heating costs. Bleeding the system regularly is crucial to avoid a build-up of air bubbles.

How We Deal With Leaks

Leaks can cause catastrophic damage to your building, so they must be identified and fixed quickly. At Akehurst, our heating engineers use thermal imaging to identify leaks in the UFH system. The main benefit of thermal imaging is that the affected area can be isolated, minimising floor damage and disruption for repairs. Post-fix pressure testing will ensure that the system runs normally.

How To Avoid Issues During Installation

Proper design and installation of your UFH system will reduce the need for maintenance and repairs, and make any necessary repairs easier. When installing a UFH system, some basic guidelines will ensure it works.

Water-based UFH systems often require a layer of screed for effective heat transfer. This will raise the floor level by ~50mm, so careful planning is essential.

The floor material over the underfloor heating system should be low resistance so that heat can be easily transferred, and the insulation throughout the building should be properly installed.

At Akehurst, our heating engineers thoroughly check the flooring and insulation, as well as the system before, during and after installation to avoid these issues.

Conclusion

Water-based underfloor heating systems are an efficient option for keeping your commercial property warm and comfortable. However, they are complex systems and issues such as leaks, airlocks, and pressure changes can be very costly if not resolved quickly.

Repairing and maintaining your underfloor heating system requires combined expertise in electrical systems and plumbing. At Akehurst, our teams of experienced heating engineers and plumbing contractors are experts in underfloor heating systems and can help with maintenance, repairs and installation. Head over to our heating and plumbing services page if you have any underfloor heating queries.

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