HIU Knowledge Base
Practical guides, troubleshooting advice and maintenance tips from London's specialist HIU engineers. Written for residents, property managers and landlords.
They both give instant heating and hot water, but work completely differently. A side-by-side comparison of Heat Interface Units and combi boilers — efficiency, running cost, servicing, lifespan and which suits a flat.
Read guideA complete guide to how HIUs work, how they differ from boilers, the main components inside, and which brands are most common in London.
Read guideLost 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 guideWhat 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 guideHIUs 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 guideTransparent pricing guide covering annual HIU service, emergency repair, installation, powerflush and bulk servicing contracts. Know what to expect before you call.
Read guideSame-day emergency response · Free quotes · Manufacturer-trained engineers