Heat Interface Unit – HIU Service London 

Need reliable service for your heat interface unit? Look no further! Our team of experienced technicians is here to help.

We have extensive knowledge and experience servicing  of HIUs an are an approved installer Redan-Danfoss SAV systems. In addition we have worked on and repaired a number of other brands.

We carry out a large number of regular and periodic servicing for our clients to ensure the HIUs are well maintained in order to minimise the risk of leaks and breakdowns. Our engineers are also repair specialist and understand the systems allowing them to correctly diagnose hot water and heating issues to  carry out necessary repairs on the first visit to recommend replacement of the correct parts.

What is a Heat Interface Unit (HIU)? 

Heat Interface Units (HIUs) look like a regular wall mounted boiler and have a similar pipe work set up to a combination boiler but they are usually a part of the heat networks mentioned above. 

They are the link between the central or communal boiler and the outlets within the property such as t radiators, showers, kitchen taps, and other hot water outlets in each unit. This means that each individual unit within a complex does not an individual boiler installed and it makes the network more efficient as a whole.

The other added benefit is the lack of need to install and run individual gas pipes to each unit. Where a gas boiler would typically need to be installed on an outside wall or a  long flue terminal, a HIU can be located anywhere or centrally as it produces no products or combustion that need to be expelled to the outside air. 

What does it cost to service my HIU?

Our competitive prices start from £75 + VAT for regularly servicing and the most common repairs of the HIU. Contact us today for further information.

How often should I service my HIU?

Whilst some manufacturers recommend annual servicing, others suggest 6 monthly servicing to ensure you are running a clean system. Please refer to your manufacturer’s HIU servicing instructions

What is involved in a HIU service?

A HIU usually entails removing and cleaning the inner filters. HIUs are usually fitted with one for the central heating circuit and one for the hot water supply. 

We also ensure the system is pressurised, the controls are functioning correctly and the safety devices are operational. 

On occasions we face very poorly systems as mentioned above and on such occasions and dependant on the severity of the issue our engineers may recommend a more detailed service which may involve removal and descaling of one or both of the plated heat exchangers

What happens after the HIU service is completed? 

We will provide you with a detailed report outlining the work that was done as well as any recommendations for future maintenance once the service or repair is completed. We also provide photographic evidence of the service or repair where required

What other related HIU Repair services do you provide?

Smart Heating Controls:

Smart Heating Controls are intelligent thermostatic controls for your heating system. You can remotely control your heating from a smartphone, tablet, or other internet-connected device that is wirelessly connected to the internet. They also help save  money on your heating bills because you have more control over your heating. Additionally, you have individual room temperature control. By not heating unused spaces, you have more opportunities to reduce your heating costs. Most common smart heating controls include thermostats and TRVs

Heat Detectors:

Installation of wires, mains and interlinked heat detectors where a smoke alarm isn’t suitable. Heat detectors are important equipment for detecting fires and ensuring safety. As the name suggests, the devices sense the temperature of a room or area in order to detect fires. Heat detectors work on a similar principle used by smoke detectors, by tracking the temperature instead of smoke.

Smoke Alarm: 

Installation of mains wired and interlinked smoke alarms, for homes, apartments, HMOs and businesses. Smoke alarms are a legal requirement for rental properties but a must have for all homes and businesses to protect lives

Power flushing: 

A method of deep cleaning your central heating system, including pipework, radiators and boiler. Power flushing improves the quality of the water contained within the system by removing the sludge and rust build up that can cause boiler breakdown or long term damage to your boiler and radiators.

Magnetic Filters: 

A device that collects debris and rust from the heating system. It can prevent damage to the boiler, leaking radiators and sludge build up within the central heating system.

Boiler Servicing: 

An annual boiler service is carrying out a series of checks and cleaning to the boiler in order to maintain and increase the life of a boiler. It is also a requirement by the manufacturer to honour any boiler guarantees. 

Boiler Installation:

We provide a variety of Gas Boiler installations including Heat Only, System Boilers and Combi Boilers. We are experienced and registered installers of all major brands such as Idea, Baxi, Main, Vaillant, Keston and many more.

Plumbing and heating:

All aspects of plumbing and heating repair, installation and servicing 

Unvented Cylinders:

Installation direct and indirect unvented cylinders. We are experienced in unvented cylinders as part of gas boiler installation, a HIU installation or stand alone electric Unvented cylinders. 

Frequently Asked Questions


How do I know if my heat interface unit is in need of repair?

Reduced hot water flow, strange noises or vibrations, and poor heating performance are all signs that your heat interface unit needs to be repaired. If you notice any of these problems, you should have your HIU inspected by a professional. 

Can I repair my heat interface unit myself?

Heat interface units are complex systems that must be repaired by someone with specialised knowledge and training. Unless you have the necessary expertise, it is not recommended that you attempt to repair your HIU yourself. It is preferable to seek assistance from a professional service provider. 

What are the common problems with heat interface units?

Reduced hot water flow, poor heating performance, and leaks or other pipe issues are all common issues with heat interface units. These issues can be caused by a number of factors, including normal wear and tear, corrosion, and poor maintenance. 

How often should I have my heat interface unit serviced?

To ensure that your heat interface unit is operating efficiently and effectively, it is recommended that you have it serviced at least once a year. If you notice any problems with your HIU, such as reduced hot water flow or poor heating performance, it is best to have it serviced as soon as possible. 

How long does a heat interface unit typically last?

With proper maintenance and care, heat interface units can last for many years. The lifespan of an HIU, on the other hand, can vary depending on a number of factors, including the unit’s quality, the level of maintenance it receives, and the local climate. 

Can a heat interface unit be retrofitted to an existing building?

Yes, a heat interface unit can be retrofitted to an existing building. Installing the HIU and necessary piping into the building, as well as connecting it to a central plant such as a boiler or district heating system, is required. 

How much does it cost to repair a heat interface unit?

The cost of repairing a heat interface unit varies depending on the nature of the problem and the extent of the repairs required. It is best to contact a professional service provider for a quote based on your unit’s specific needs. 

How much does it cost to replace a heat interface unit?

The cost of replacing a heat interface unit varies according to the unit’s size and complexity, as well as the cost of labour and materials. It is best to contact a professional service provider for a quote based on your unit’s specific needs. 

Can you install a heat interface unit in a new build?

Yes, a heat interface unit can be installed in a new build. This entails designing and installing the required piping, as well as connecting the HIU to a central plant, such as a boiler. 

What are the benefits of a heat interface unit?

Heat interface units provide several advantages, including increased energy efficiency, lower maintenance costs, and individual control of heating and hot water for each unit. HIUs can also be linked to renewable energy sources, increasing their energy efficiency even further. 

How energy efficient are heat interface units?

Heat interface units can be very energy efficient because they allow each unit to have independent control over heating and hot water. This means that rather than constantly heating a central system for an entire building, units are only heated when needed. HIUs can also be linked to renewable energy sources, increasing their energy efficiency even further. 

Are heat interface units noisy?

Heat interface units can make some noise while operating, but this is usually minimal and should not be bothersome. If you notice excessive noise coming from your HIU, it could be a sign of a problem that requires professional attention.

Do heat interface units require a lot of maintenance?

Heat interface units do necessitate some maintenance in order to function efficiently and effectively. This can include both annual servicing and routine inspections and cleaning. However, because an HIU only serves individual units rather than an entire building, its maintenance is typically less than that of a traditional central heating system.

How can I tell if I have a HIU or a combi boiler in my property?

Having a gas supply is usually a good clue, combi boilers require a gas supply to operate and an external flue to get rid of the fumes. A HIU unit is not connected to a gas supply and does not have a flue

Why do I have hot water but the heating is not working on my HIU?

Seized parts and components on HIUs are common causes for the heating not working. Due to lack of usage during the summer months parts such as the pump can seize causing the heating not to circulate, but the hot water remains functional. It is a good idea to turn your heating on a few times over the summer to make these parts run. 

My HIU has been serviced but I still have no heating or hot water?

This could be a communal issue, HIUs are supplied by a main central boiler that provides the source of hot flow and their only function is to take this heat and distribute within the property. If the communal or central boiler isn’t working and cannot supply a flow of hot water they cannot operate.

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