Our HIU Services
Specialist Heat Interface Unit installation, servicing and repairs — keeping your property's heating and hot water running efficiently.
HIU Installation
Professional Heat Interface Unit installation for new builds, refurbishments and replacements. We supply and fit all major HIU brands to the highest standards, ensuring optimal performance from day one.
- New Build Installations
- HIU Replacements & Upgrades
- All Major Brands Supplied
- Commissioning & Testing
HIU Servicing
Keep your Heat Interface Unit running efficiently with regular servicing. Our engineers provide thorough inspections, descaling, and component checks to prevent costly breakdowns and extend unit lifespan.
- Annual Servicing Plans
- Descaling & Flushing
- Performance Testing
- Filter & Component Checks
HIU Repairs
Fast, reliable HIU repair services when you need them most. We diagnose and fix faults on all major HIU brands to restore your hot water and heating quickly with minimal disruption.
- Emergency Repairs
- All Major Brands
- Same-Day Service Available
- Fault Diagnostics & Parts Supply
HIU Powerflush
Professional powerflushing to remove sludge, scale and corrosion debris from your HIU and heating system. Restores efficiency, improves flow rates and extends the lifespan of your unit.
- Full System Powerflush
- Sludge & Scale Removal
- Improved Heating Efficiency
- System Inhibitor Treatment
Bulk Servicing
Block-wide HIU service contracts for property managers and housing associations. Coordinated resident access, discounted multi-unit rates, and full reporting across your entire building.
- Discounted Block Rates
- Resident Access Coordination
- Mixed-Brand Coverage
- Full Compliance Reporting
Danfoss HIU Repair
Specialist Danfoss HIU repair and service in London. Manufacturer-trained engineers, parts on the van.
- Akva Lux & FlatStation
- PICV & Actuator Repair
- Plate Heat Exchanger Descale
- Error Code Diagnosis
SAV HIU Repair
Expert SAV HIU repair and servicing in London. Same-day response for SAV Ultraheat and Apollo faults.
- SAV Ultraheat & Apollo
- Diverter Valve Repair
- Control Board Diagnosis
- Emergency Callout
Caleffi HIU Service
Caleffi HIU repair and annual servicing in London. Thermostatic cartridge and valve specialists.
- CaleffiStation Units
- Thermostatic Cartridge
- Pressure Relief Valves
- Flow Balancing
Switch2 HIU Repair
Switch2 HIU and metering fault repair in London. Full system diagnostics including billing units.
- Switch2 Metering HIUs
- Control System Errors
- Valve & Actuator Faults
- Metering Diagnosis
HIU Service Plans
Monthly HIU service plans from £19.99/mo. Cover your labour, unlimited callouts and parts — one fixed fee, no surprise bills. Two simple plans: Basic and Premium.
- From £19.99/month
- Unlimited Callout Claims*
- All Parts Covered (Premium)
- Free Initial Inspection
Need Help With Your HIU?
Get in touch today for a free, no-obligation quote from our expert HIU engineers.
About HIU Service & HIU Repair in London
In short
Collide Group provides five core HIU services across London: HIU servicing (annual maintenance from £120), HIU repair (same-day emergency callouts), HIU installation (new builds and replacements), HIU powerflushing (sludge and scale removal) and bulk servicing (block-wide contracts for property managers). All major brands are covered, including Danfoss, SAV, Switch2 and Caleffi.
Collide Group is a specialist Heat Interface Unit (HIU) engineering company based in Northolt and serving all of Greater London. We are Gas Safe registered and WRAS certified, with over 10 years' experience, specialising in HIU service, HIU repair, HIU installation and HIU power flushing. A Heat Interface Unit (HIU) is the compact heat exchanger fitted in flats and apartments connected to a communal or district heating system. It transfers heat from the building's central plant room into your home for hot water and central heating, replacing the traditional individual boiler.
Our manufacturer-trained engineers service, repair and install every major HIU brand used across the UK including Danfoss, SAV, Switch2, Caleffi, Alfa Laval, Heatweb, Thermal Integration and Redan.
Annual HIU Service from £120
Our annual HIU service follows a 30-point checklist covering strainer cleaning, plate heat exchanger inspection and descale, valve and actuator testing, temperature and flow performance, control verification and a full written report.
Same-Day HIU Repair Across Greater London
Lost hot water or heating? We offer same-day emergency HIU repair across Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Wandsworth, Westminster and the wider Greater London area.
Call 020 3951 5133 for a free quote, or book online — we respond within one working hour.