Case Studies / Dunfermline
Heat Networks · Dunfermline, Fife

Dunfermline District Heat Network — HIU Replacement Programme

A major Heat Interface Unit (HIU) replacement and modernisation programme across three occupied residential tower blocks connected to one of Scotland’s established low-carbon heat networks.

Client
Switch2 Energy Ltd (for Fife Council)
Location
Dunfermline, Fife
Network type
District heating
Properties served
Three residential tower blocks
Project type
Asset upgrade & modernisation
Contractor
EMG Installations Ltd
Emergency response
Under 3 hrs (4-hr target)
Status
Completed — ongoing O&M in place
Insulated district heating pipework and plant on the roof of a residential development
3 blocksHIUs replaced
& modernised
Overview

Modernising an ageing district heating asset

EMG Installations Ltd was appointed by Switch2 Energy Ltd, on behalf of Fife Council, to deliver a major HIU replacement programme across three residential tower blocks on the Dunfermline District Heat Network. The works comprised the removal of obsolete Vital Energi AquaVarm units, upgraded resident heating controls, efficiency improvements and extensive secondary-system cleansing to protect the long-term performance of the infrastructure.

The network is fuelled primarily by renewable and recovered energy: heat recovered from waste at the Dunfermline Recycling Centre, supplemented by a biomass woodchip boiler and back-up plant at the Broomhead Energy Centre. All works were carried out in occupied homes, in close coordination with residents, housing representatives and network operators.

Scope of works

HIU, controls, metering and system cleansing

Wall-mounted heat interface unit with valves, pump and expansion vessel in a modern flat
Technical solution

ICON HIUs with remote monitoring, controls & metering

The end-of-life AquaVarm units were replaced with modern ICON Heat Interface Units, offering improved reliability, efficiency and maintainability. The ICON units support advanced remote monitoring — real-time performance data, early fault detection, proactive maintenance planning and faster response — with access shared between Switch2 and EMG for a collaborative approach to network management.

Alongside the HIUs, new Switch2 Incontro controls and heat meters were installed and integrated with the district heating monitoring platform, giving residents better control of their heating and hot water while enabling accurate energy monitoring and billing. The combined solution also brings the network in line with the BESA 2027 requirements for heat network operators.

System improvement works

Protecting long-term system performance

1

Chemical cleansing

Specialist cleanser introduced to break down sludge, corrosion products and debris in ageing secondary systems.

2

Kamco power flushing

A full power flush of each system to restore circulation, heat transfer and radiator performance.

3

Water quality testing

Post-flush verification of water clarity and contaminant removal, recorded as part of commissioning.

4

Filtration & protection

Adey Atom magnetic filters and corrosion-inhibitor dosing to extend equipment lifespan.

Challenges

Working within occupied residential tower blocks

The programme was delivered in live, occupied residential buildings, requiring careful coordination and clear communication to keep heating and hot water running wherever possible.

  • Coordinating access to a large number of dwellings across three blocks
  • Managing resident expectations through clear, consistent communication
  • Bringing ageing secondary heating systems up to a consistent standard
  • Maintaining service levels throughout the works
Engineer in a hard hat checking pumps and pipework in a commercial plantroom
3
Tower blocks modernised
100%
AquaVarm HIUs replaced with ICON units
<3 hrs
Emergency response against a 4-hr target
O&M
Ongoing maintenance contract awarded
Outcomes

Reliable heat and a long-term maintenance partnership