HIU Repair London Heat Interface Unit
No Hot Water Or Heating?
Expert HIU Repair
Many standard plumbers and gas engineers frequently misdiagnose HIU faults, often blaming everything on a blocked plate heat exchanger. Sound familiar? At R&B London HIU Engineers, we specialise exclusively in HIU diagnostics and repairs. Our engineers carry fully stocked vans with the most common parts for Evinox, Danfoss, Caleffi and other major HIU brands allowing many repairs to be completed on the first visit.
We provide fixed-price repairs, expert fault diagnosis, and all repair works come with a 12-month warranty for peace of mind. Our company is also fully insured with £5 million public liability cover.
Common HIU Faults
No Hot Water
Blocked strainer, faulty actuators, sensors, or a blocked plate heat exchanger are common causes. Our HIU specialists carry diagnostic tools and common replacement parts to identify the fault and restore hot water as quickly as possible.
Cold Radiators
Usually caused by stuck control valves, circulation pump issues, or restricted flow. Our engineers diagnose the heating circuit and replace faulty components where required.
HIU Leaking
Leaks can occur due to worn seals, PRV discharge, or internal component failure. We locate the source of the leak and repair or replace the affected parts before pressure testing the unit.
Noisy HIU
Often caused by air in the system, low pressure or crossed flow. We inspect internal components, clean filters, and correct flow restrictions to reduce noise.
How Our HIU Repair Service Works
Transparent diagnosis, fixed-price repairs, and no work carried out without customer approval.
Expert Diagnosis
Our engineer first checks whether the issue comes from the communal heating system before inspecting the HIU itself. Once confirmed within the unit, we carry out a full diagnosis to identify the exact cause of the fault.
Fixed Price Repair
If the issue can be repaired during the visit, our engineer will fix it on the spot. When replacement parts are required, we confirm the cost with the customer before fitting any components.
Report & Follow-Up
You receive a detailed PDF report with photos of the work carried out. If a required part is not available in our vans, we provide a fixed-price quote to supply and install it.
What Our Customers Say About Our HIU Repairs
HIU Breakdown & Repair Rates
Monday to Friday
8am to 5pm
Per hour (1 hour minimum charge)
- Congestion charge included
- No driving charge
- No parking charge
- Full report with photos
R&B Returning Customers
Forever 20% Discount
Per hour (1 hour minimum charge)
- 8am to 5pm Mon - Fri
- Congestion charge included
- No driving charge
- No parking charge
- Full report with photos
Out Of Hours
Emergency 24/7
Fixed price for 1st appointment
- 5pm to 7am any day
- 24h Weekends & Bank Holidays
- Congestion charge included
- No driving/parking charge
- Full report with photos
Book Your Specialist
Same-day emergency response across all London postcodes.
Plantrooms
Packages available
PLANTROOMS
Many packages available to suit your needs. Contact us today for a free quote.
COMMUNAL & DISTRIC HEATING
Gas boiler service
Coming soon
WATER TREATMENT
Coming soon
MONTHLY CHECKS
Coming soon
PPM
Coming soon
System balancing
Coming soon
FREE QUOTE
Or Call 0800 195 6468
HIU REPLACEMENT
coming soon
Tado Heating Programmer & Smart Radiator Thermostat
Schedule Install
Or Call 0800 195 6468
HIU SERVICE (Heat Interface Unit)
Professional HIU Servicing
in London
Fixed-price HIU servicing for residents, landlords and managing agents across London. Choose from Standard, Advanced or Premium service options, all carried out by specialist HIU engineers with PDF reporting after the visit.
What is included in our HIU service?
Our HIU service is designed to improve performance, reduce the risk of breakdowns and highlight worn components before they fail. We follow a structured servicing process and issue a digital PDF service report after the visit.
- Primary filter or strainer clean
- Visual inspection for parts functionality and leaks
- Hot water performance test
- Heating performance check
- Pressure top up
- Basic electrical safety checks
HIU service packages
Choose the level of servicing that suits your system. All packages are carried out by HIU specialists and priced clearly before the visit.
Standard
Ideal for routine annual HIU servicing and general condition checks.
- HIU service certificate (PDF) ✓
- Primary filter or strainer clean ✓
- Leak and corrosion inspection ✓
- Hot water performance test ✓
- Heat meter functionality test ✓
- Communal flow verification ✓
- Expansion vessel health check ✓
- DPCV or PICV calibration ✕
- System inhibitor top-up ✕
Advanced
A more detailed HIU service with deeper checks and performance-focused testing.
- Includes Standard service items ✓
- DPCV or PICV calibration ✓
- Heat meter and flow logging ✓
- Isolation valve operation check ✓
- Electrical safety and earth test ✓
- Cylinder health check ✓
- System inhibitor top-up ✕
- Radiator venting and balancing ✕
- UFH manifold maintenance ✕
Premium
Best for systems needing broader balancing, calibration and deeper performance checks.
- Includes Advanced service items ✓
- System inhibitor top-up ✓
- Radiator venting and balancing ✓
- Underfloor heating calibration ✓
- Sealing washer replacement ✓
- Actuator stress testing ✓
- Full thermal imaging audit ✓
Combined HIU & MVHR servicing
Save time and reduce callout disruption by booking your HIU and MVHR service together. We also offer a group booking system where we provide a project code that you can share with residents or neighbours, allowing them to book their own preferred day and time slot and reschedule if needed. This removes admin work for managing agents and makes larger bookings much easier to organise.
Book Combined ServiceGroup and block discounts
Preferential fixed pricing is available for multiple HIU service bookings in the same building. Ideal for block managers, landlords and coordinated resident bookings.
2 to 5 Units
6 to 9 Units
10 Plus Units
What our customers say about our HIU service
Reviews from residents and property professionals across London who booked HIU servicing with our engineers.
HIU service FAQs
How often should a HIU be serviced?
Most HIUs should be serviced every 12 months to help maintain performance, reduce energy waste and lower the chance of unexpected breakdowns.
Will I receive a service certificate?
Yes. After the service, we provide a PDF HIU service report and certificate. Where relevant, this can also include photos and notes on any faults found.
Do you service different HIU brands?
Yes. We work on a wide range of HIU makes and models used across London developments, including common systems found in residential blocks and apartments.
Book your HIU service
Our office will review your request and contact you to confirm the appointment. Fixed-price options available across London.