Caleffi HIU Repair & Servicing Specialists in London
HIU Experts provides expert repair and maintenance services for Caleffi Heat Interface Units (HIUs) in London. From no heating and no hot water call-outs to annual servicing, we fault-find and repair Caleffi HIUs in single flats and whole apartment blocks.
What is a Caleffi HIU?
A Caleffi HIU (Heat Interface Unit) is the unit inside a flat that takes heat from a communal or district heating network and passes it to the flat's own heating and hot water, without a boiler or hot water cylinder. Caleffi HIUs are widely used across London residential and communal heating installations.
Because a Caleffi HIU combines a plate heat exchanger, control valve and actuator, strainer, sensors, pump and electronic controls in one compact cabinet, faults are rarely obvious from the outside. Each Caleffi model has its own control logic and component layout, so accurate fault finding matters. We diagnose Caleffi units against their specific control logic, so faults are found faster and fixed right first time.
Whether you are a leaseholder, tenant, landlord or managing agent, our Caleffi HIU service in London keeps units efficient, reliable and working within manufacturer specification.
How a Caleffi HIU delivers heat and hot water
01
Primary supply enters the unit
Hot water from the building's heat network arrives at the HIU through isolation valves and a strainer that protects the components downstream.
02
Control valve and actuator regulate flow
The control valve, driven by an actuator, meters primary flow to match heating and hot water demand and keeps the return temperature in check.
03
Plate heat exchanger transfers heat
Heat passes from the primary side to the flat's own heating circuit and to domestic hot water, without the two water systems mixing.
04
Sensors and control panel manage the system
Temperature sensors and the electronic controller monitor flow and return temperatures and respond when you open a tap or call for heat.
05
Cooled water returns to the network
The primary return leaves the unit. A high return temperature is a common sign that something inside the HIU needs attention.
Caleffi HIU Servicing in London
Keep the unit efficient and operating within manufacturer specification. A Caleffi HIU service from HIU Experts includes:
Strainer inspection and cleaning to protect the components downstream
Plate heat exchanger performance checks to catch fouling early
Control valve and actuator testing for correct, stable operation
Flow and return temperature verification against expected values
Sensor, pump and control panel checks for faults and error readings
Leak and pressure checks across the unit and its connections
Caleffi HIU Service, Repairs & Maintenance
Expert maintenance, repairs and installations for Caleffi HIUs across London, all carried out by engineers who work on heat interface units every day.
Caleffi HIU Fault Finding & Diagnosis
Accurate diagnosis of no heat, no hot water and intermittent HIU faults.
Plate Heat Exchanger Repair
Cleaning, descaling or replacement when fouling affects hot-water output.
Control Valve & Actuator
Diagnosis and replacement of components affecting flow and temperature control.
Sensors & Control Panel
Diagnostic checks carried out against Caleffi control logic and system performance.
Caleffi HIU Service and Repairs Gallery
Examples of the Caleffi heat interface units our engineers repair, service and maintain.
Caleffi HIU servicing
Strainer, plate heat exchanger, valve and temperature checks.
Caleffi HIU repair
Fault finding, component replacement and performance testing.
Why Choose HIU Experts for Caleffi HIU Repair?
We diagnose Caleffi units against their specific control logic and component layout, helping faults get found faster and fixed right first time.
HIU specialists, not generalists
Heat interface units are all we do. That means plate heat exchangers, control valves, actuators, strainers, pumps and controllers are familiar ground, not an occasional job.
Diagnosis before parts
We confirm the fault with readings and tests before replacing anything, so you pay to fix the actual problem and not to guess at it.
Fixed-price repairs
You get a clear fixed price once the fault is diagnosed and before any work begins. Call or WhatsApp and we will confirm the fastest available appointment.
HELPFUL ANSWERS
Frequently Asked Questions About Caleffi HIUs
- 01
- 02
- 03
- 04
- 05
- 06
Related HIU Services
Emergency and standard repairs
Danfoss units
Annual and one-off servicing
Evinox units
New and replacement units
Intatec, Oventrop, Kamo and more
Planned and reactive cover
Meters and prepay systems