MTA Plus TWIN

Heat Interface Unit

The MTA Plus heat pump optimised heat interface unit is designed for use within Heat Networks where heat pumps or a traditional gas fired boiler plant provides the source of energy. This indirect twin plate 'one size fits all' solution ensures low return temperatures at all primary flow temperatures, which is key to obtaining high heat network efficiency and low operational costs.

5

5 Year
Warranty*

WRAS

WRAS Approved
#2011358

BESA

BESA
Registered

Unique HydraBlok® back plate

Most other heat interface units available on the market are often a myriad of metal pipework and brass fittings. With this type of HIU every union is a potential source of a water leak, as the unions often loosen during transportation from the factory to the point of use. The MTA has little potential for leaks as it is not fitted with metal pipework and brass fittings. Everything is built upon a unique HydraBlok® backplate which contains all waterway channels moulded within a composite chassis.

Advanced pump control (anti-seizure)

The MTA runs an automatic 24-hour anti-seizure cycle — if the heating circuit has not been used for 24 hours, the pump and heating regulation valve are exercised for 10 seconds to prevent debris build-up in the pump bearings. If the heating circuit pressure falls below 0.4 bar, the pump is stopped and an error is displayed, protecting the pump from running dry in the event of a leak. Domestic hot water production continues unaffected.

Return temperature limitation

To ensure the heat network operates at maximum efficiency, the MTA will modulate the rate of water flow provided by the internal apartment heating circuit pump to match the heat load of the apartment at any one time. This maintains the designed heating circuit ΔT and limits the temperature of the water returning to the primary circuit.

Primary flow rate limitation

The MTA can limit the primary flow rate in both DHW and heating mode, independently of each other. Limiting the maximum flow rate that the HIU can take from the primary system, during space heating production, guarantees the design flow rate used to calculate system demand is not exceeded, protecting the heat network from excessive primary draw during periods of high demand or cold weather.

  • 2023 BESA HIU Test Passed,
    7 Best Practices Achieved

  • SWEP LAS AISI 316 heat exchangers

  • Ultra-compact dimensions

  • Fully electronic unit

  • Keep warm function (On/Off/Timed)

  • DHW priority

  • 16 bar rated

  • Advanced diagnostics

  • Remote connectivity

  • Automatic low heating circuit pressure cut out

  • Provision for fitting of underfloor safety thermostat

  • First fix kit supplied as standard

  • Compatible with smart home controls

  • Weather compensation functionality (sensor required)

  • Servicing and parts replacement from front

  • Integrated apartment quick-fill device

  • Isolation & drain valves fitted as standard

  • Labelled water connections

  • Underfloor or radiator temperature set-points

  • PWM controlled A-rated modulating heating pump

  • Closed-cell foam insulation cover

  • Prepayment cut off

  • Optional flushing bypass valve available

  • Optional top entry pipe kits available

*Subject to Terms & Conditions

Downloads

Features in detail
Advanced diagnostics

The control panel within the MTA provides a user friendly, intuitive experience. In addition, it provides an extremely high level of real time data, offering an overview of the current conditions within the network, HIU and apartment.

1
Primary flow temperature
2
DHW temperature
3
MCW temperature
4
Primary return temperature
5
District modulating valve stepper motor position (0 to 250)
6
DHW flow rate
7
DHW regulation valve stepper motor position (0 or 250)
8
Heating regulation valve stepper motor position (0 or 250)
9
Heating flow temperature
10
Heating pressure
11
Heating flow rate
12
Heating return temperature
13
Primary flow rate
ModuHub (optional extra)

The MTA has Modbus remote read/write communication built in as standard, allowing each HIU to be remotely monitored via the building's BMS to capture temperatures and operating parameters. ModuHub extends this to full remote monitoring and control, enabling network operators to continuously optimise their heat networks, resolve faults remotely, and reduce the number of planned maintenance visits to site. ModuHub also creates an open protocol wireless billing network, removing the requirement for an M-Bus network. Heat meter reads are retrieved by billing providers via LoRa communication, and the system supports both prepayment and credit billing. The ModuHub module is compact enough to fit within the MTA casing.

What is a heat network?

A heat network – also called district heating – is a distribution system of insulated pipes that takes heat from a central source and delivers it to a number of domestic or non-domestic buildings.

Learn more

What are the benefits of HIUs?

Heat Interface Units (HIUs) are the smart solution for modern district heating and communal heating systems, delivering exceptional value for developers, residents, and building managers in apartment blocks and multi-dwelling properties.

Space-saving and cost-effective for multi-dwelling developments

HIUs eliminate individual boilers in each flat, reducing capital costs and freeing up valuable space. With no gas supply infrastructure or flues required, construction is simpler and more cost-effective for apartment blocks and residential developments. At just 600 x 500 x 312mm, our MTA HIUs fit neatly into a cupboard. Centralised heating means one efficient plant room instead of servicing hundreds of individual boilers—ideal for social housing, student accommodation, and new build projects.

Instant comfort with instantaneous hot water

Residents enjoy instant domestic hot water (DHW) without waiting, plus precise space heating control for underfloor heating (30-45°C) or radiators (45-80°C). Our twin plate HIU design operates quietly with no combustion in dwellings—eliminating gas pipes and carbon monoxide risks. Advanced diagnostics with remote monitoring enable quick issue resolution, often without site visits.

Energy efficiency and heat pump optimised performance

District heating networks with HIUs enable efficient heat generation from combined heat and power (CHP), renewable sources, or heat recovery systems. Modern HIUs are specifically heat pump optimised for low temperature heat networks, ensuring exceptional return temperature performance for maximum efficiency and reduced operational costs. The MTA Plus Twin passed the 2023 BESA HIU Test with 7 Best Practices Achieved, recording VWART scores of 26°C (high temperature) and 24°C (low temperature). As the grid transitions to renewable energy, your entire building benefits automatically.

Smart metering and heat network management

Integrated heat metering ensures residents pay only for the energy they use, promoting fairness and energy-conscious behaviour in apartment complexes. Optional remote connectivity and building management system (BMS) integration provide real-time performance data for continuous heat network optimisation whilst reducing maintenance visits—perfect for managing communal heating across residential buildings.

Technical Data

Primary Circuit (district)
Max operating pressurebar16
Maximum supply temperature°C85
Min/max differential pressurebar0.5/4
Domestic Hot Water (apartment)
Maximum heat exchanger capacitykW107
Hot water set-point°C40-60
Maximum cold feed supply pressure bar10
Heating (apartment)
Maximum heat exchanger capacitykW27
Heating water set-point (underfloor)°C30-45
Heating water set-point (radiators) °C45-80
Maximum operating pressure bar2.5
Safety valve settingbar3
Circulating pumpWilo Para 8-75
Expansion vessel volumelitres10
Heating control (room thermostat) Volt free
General
Dimensions (HxWxD)mm600 x 500 x 312
Water connectionsmm18/22
Weight (HIU)kg24
Weight (first fix kit)kg4
Electrical
Mains supply230-1-50
Power consumptionW85
ProtectionIP44
Connections
District inletBSPG 3⁄4"
District returnBSPG 3⁄4"
Heating flowBSPG 3⁄4"
Heating returnBSPG 3⁄4"
Domestic hot water outletBSPG 3⁄4"
Mains cold water inletBSPG 3⁄4"
Domestic cold water outletBSPG 3⁄4"
Pressure relief valve drainBSPG ½"

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