HIU Basics6 min read
What Is a Heat Interface Unit (HIU)?
A complete guide to how HIUs work, how they differ from boilers, the main components inside, and which brands are most common in London.
Read guideHIU Knowledge Base
HIU Guides & Expert Advice
Practical guides, troubleshooting advice and maintenance tips from London's specialist HIU engineers. Written for residents, property managers and landlords.
Troubleshooting5 min read
Why Has My HIU Lost Hot Water?
Lost hot water from your HIU? We cover the most common causes — blocked plate heat exchanger, failed valves, PCB faults — and what an engineer will do to fix each one.
Read guideFault Codes5 min read
HIU Fault Codes Explained — Danfoss, SAV & Switch2
What do HIU error codes mean? We explain the most common fault codes on Danfoss, SAV and Switch2 HIUs and whether you can safely reset them yourself.
Read guideMaintenance4 min read
How Often Should an HIU Be Serviced?
HIUs should be serviced annually — just like a boiler. Find out what's included in a professional HIU service, why it matters, and what happens if you skip it.
Read guidePricing5 min read
HIU Service & Repair Cost in London (2026 Guide)
Transparent pricing guide covering annual HIU service, emergency repair, installation, powerflush and bulk servicing contracts. Know what to expect before you call.
Read guideNeed an HIU Engineer in London?
Same-day emergency response · Free quotes · Manufacturer-trained engineers