Double flow rooftop heat pump with recovery module: ULTI+ DX

ETT has developed a new generation of rooftop units: ULTIMA. This Eurovent certified range is the fruit of many years of experience in Ecodesign and modular heat pumps production. The ULTI+ is ERP2021 ready and combines energy efficiency and acoustic performance. It includes a new generation control system that ensures unit optimal operation at all times.

The modular design of the ULTIMA range allows you to adapt unit capacity to your needs. You may choose to install the standard ULTI+ heat pump, or to customise the packaged unit with additional modules such as a rotary heat exchanger, creating an ULTI+ DX unit and adapting its performance to the environment and requirements of your application.

Ulti+ DX


The ULTI+ DX is covered by a 20-year guarantee against corrosion

The ULTI+ DX heat pump offers fully optimised air treatment. Thanks to its full aluminium structure (frame & casing) that ensures an excellent corrosion protection, this air conditioning and heating system is covered by a 20-year guarantee against corrosion (frame and casing). The DX extraction and energy recovery module enables heat recovery on exhaust air thanks to its rotary exchanger, reducing the unit operating costs. Building pressure management is ensured by an integrated extraction module. It is recommended for applications requiring an air change of 50% fresh air or less. This single flow rooftop heat pump is delivered ready to operate. The separate technical section facilitates service and control of the unit and allows measurement and adjustment during operation. Performance and ease of installation are the key elements of the ULTI+ DX: it is particularly adapted for treating large volumes and its standard frame and roof curb facilitate roof installation. The ULTI+ DX is a NEW GENERATION single flow heat pump designed to offer optimum air quality.

The ULTI+ DX unit operates as a reversible heat pump:

  • Source: outside air
  • Treated fluid: inside air

The unit offers several operating modes:

  • Heat pump
  • Cooling
  • Free Cooling: cooling with outside air, without thermodynamics

In those cases, the ULTI+ DX rooftop unit operates:

  • With all recirculated air during vacancy periods or when no hygienic fresh air is required
  • In Cooling/Heating mode
  • Free Cooling with max. 50 % fresh air compared to rated air flow rate.

The ULTI+ module offers several operating modes:

  • Heating mode: In winter, comfort temperature is maintained thanks to the thermodynamic system and auxiliary heaters (optional).
  • Cooling mode: In summer, comfort temperature is maintained thanks to the thermodynamic system.
  • Free Cooling mode: In mid-season, comfort temperature is maintained using in priority the difference between outside air and inside air to cool the building. Free Cooling allows considerable savings by delaying the use of thermodynamics.
  • Recycling mode: Destratification through air recirculation, when return air temperature is significantly higher than room temperature.

The ETT packaged unit comprises 4 different sections:

  1. The external section allows thermal exchanges with the environment.
  2. The separate technical section houses the refrigeration components, the electrical board and the control components.
  3. The internal section ensures air change and air treatment.
  4. The separate technical section houses the refrigeration components, the electrical board and the control components

Available options

Frame – Casing

  • Double skin on internal section
  • Motorised external damper on supply air, except downwards (2006/42/EC Directive)


  • Low Noise EC supply air and exhaust air fans Exhaust air box sound insulation
  • Compressors acoustic jackets

Air handling

  • Actuating smoke detector with battery back-up
  • Epoxy coating on supply air and exhaust air fans
  • Epoxy coating on rotary exchanger
  • Pressure gauges for supply air filters
  • Refillable 98 mm G4 filters on supply air with analogue probe
  • 98 mm M5 filters on supply air with analogue probe
  • G4 + F7 double filters or F9 filters (48 + 48 mm) on supply air with analogue probe
  • 98 mm F7 filters on supply air with analogue probe
  • 98 mm F9 filters on supply air with analogue probe


  • ETT SRV control (variable cooling system)
  • Cooling only operating mode (non-reversible unit)
  • Compressor MAP monitoring
  • Vinyl coating on thermodynamic coils
  • Refrigerant leak detection aid
  • HP and LP pressure gauge


  • Recovery hot water coil with analogue frost protection thermostat
  • Auxiliary hot water coil with analogue frost protection thermostat
  • Progressive 3-way valve for hot water coil
  • Stop valve on outlet + TA regulating valve on inlet for hot water coil
  • Auxiliary 2-sequential stage electric heaters + Load shedding using dry contact
  • Fresh air preheating through auxiliary 3-stage electric heaters


  • Total electrical energy metering according to 2002/91/EC
  • Aluminium/copper connection terminal blocks (aluminium mandatory for power cables)
  • 230V/16 A single-phase socket in the technical section (separate power supply to be provided by the installer)
  • Phase checker
  • IT earthing system compatibility
  • Cable protective cowl for outside power supply (to be mounted by the installer)


  • Aluminium adjustable connection roof curb
  • Aluminium adaptation connection roof curb
  • Aluminium adjustable ventilated roof curb
  • Aluminium ventilated adaptation roof curb
  • Aluminium plenum for return air and supply air
  • 200 or 400 mm aluminium feet


  • Operation in year-round mode (compressor authorisation in Cooling mode with outside temp. < +15°C)
  • Control function in Comfort mode (setpoint temperatures control by PID)
  • Free Cooling banning based on specific humidity comparison
  • VDP operation (power/flow rate variation)
  • HPE+ operation (High Energy Performance)
  • Dehumidification function level 1 (without heating capacity recovery)
  • Dehumidification function level 2 (with heating capacity recovery & on/off refrigerating 3WV)
  • Dehumidification function level 3 (with heating capacity recovery & analogue refrigerating 3WV)
  • Average room temperature (4 probes)
  • Minimum fresh air slaving using turret contacts (2 maximum)


  • myETTvision
  • ETT TouchScreen remote touchscreen display
  • Modbus RS485
  • Modbus IP
  • BACnet IP
  • LonWorks
  • Konnex

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