The Small Y (PUMY) series of outdoor units by Mitsubishi Electric, which now offers 7 different variants (with single and three-phase 4.5, 5 and 6 HP versions and a three-phase 8 HP version), is the ideal solution for large homes and medium-sized offices. These outdoor units may be connected to up to 12 indoor units of different type and power rating. This system offers exceptional savings in operating costs and is suitable for both residential and commercial applications


Class-beating energy efficiency

The new Small Y (PUMY) series has been designed to offer extraordinary levels of energy efficiency in both summer (EER) and winter (COP) operation.

The entire range scores COP values above 4, making these units usable even in regions where legislation sets more restrictive performance limitations.

Total comfort. Even at -20°C

The new Small Y (PUMY) series is now capable of operating in heating mode over an even broader temperature range (from -20 to +15 °C).

New chassis with larger heat exchange surface area

The new design of the Small Y (PUMY) series has made it possible to use a direct expansion coil with greater heat exchange surface area and density.

Together with the introduction of the Heat Inter Charger overcooling circuit – a technological solution now appearing for the first time in units of this series – these improvements ensure superlative performance and extraordinary energy efficiency in cooling mode.

The flat fin configuration of the coil and special Blue Fin treatment protect the coil itself against corrosion, ensuring that the unit continues to function with the same outstanding thermal exchange efficiency and performance over time.

The power of a VRF, the elegance of a residential Multi-Split

With the LEV KIT and the new dedicated Branch Box*1 (available as 3 and 5 connection versions), the outdoor units of the Small Y series can now be connected to the entire range of residential and commercial*2 indoor units, with looks that are perfectly suited to applications (such as residential buildings and hotels) where design and elegance are decisive factors in the choice of indoor units.

New Branch Boxes (3 or 5 connections) – Total flexibility

The new Branch Boxes are designed to offer the greatest configuration flexibility possible for the system.

This makes it possible to create systems consisting entirely of CITY MULTI VRF units, systems with Residential/Commercial series indoor units only, or mixed systems with both types of unit.

Total flexibility for installation and maintenance

With increased geometric limits for piping, the Small Y (PUMY) series offers unparalleled flexibility for installation.

Mixed systems

Small Y series (PUMY) sizes 4.5-5-6 HP can be connected to Ecodan HYDROBOX and HYDROTANK, allowing mixed systems (domestic hot water, radiant panels or air heating and air cooling).

Thanks to this feature the system can produce hot water up to 55°C.


Unparalleled silence

The new fans cut through the air more effectively and minimise turbulence, for superlative static overpressure with minimum noise impact.

These fans generate a 10% higher outdoor air flow than the previous version while operating at the same noise levels.

Small Y (PUMY) is also capable of operating in “low noise” mode, reducing sound pressure levels by 2 dB.

By connecting an external timer or switch to the fan, this mode can be set for specific time brackets during the day.

New fan

Diameter increased from 490 mm to 550 mm.

The new fan has longer, differently shaped blades to direct air more effectively, reduce turbulence and increase efficiency.

New PUMY Y(V)KM with Replace Technology

The EU regulation 2037/2000/EC has banned the use of virgin HCFC refrigerants (R22) since 1/1/2010.

As a result, in the event of a fault or even just a refrigerant leak in an air conditioning system using R22, it is no longer possible to recharge the system.

With small to medium-sized installations in particular, the most cost effective solution is to replace the entire air conditioning system.

This is because of the following reasons:

  • New generation outdoor units with R410A are much more efficient, with lower electric power consumption;
  • They are quieter and offer more effective air filtration;
  • Taking advantage of tax rebates offered for replacing winter air conditioning systems will minimise the time necessary to recoup the initial outlay.

The main problem in replacing an existing air conditioner using R22 fluid with a system using new R410A refrigerant is posed by the residue of chlorine and mineral oils remaining in the existing piping onto which the air conditioner system containing R22 was connected.

This residue is extremely harmful for the new air conditioner, and unless the circuit is flushed out extremely thoroughly, may degrade the new oil and/or cause obstructions in the refrigerant circuit and, as a result, lead to system malfunctions. Moreover, the diameters and thickness of the existing piping may not be compatible with the new units.

The Small Y (PUMY) Lines of outdoor units features Mitsubishi Electric Replace Technology, which allows the existing piping to be used without modification, even with piping with different diameters and wall thicknesses.

By using exclusive HAB oil and special low friction technology for the compressor, the majority of our air conditioners may operate with the original piping, cutting installation times and costs and material costs while minimising environmental impact.

AC PRE-HEATING compressor pre-heating system

An AC pre-heating system is used for the compressor.

The pre-heat routine is based on the temperature of the refrigerant and of the compressor.

AC control reduces power absorption in stand-by state, increasing seasonal efficiency.


Technical data sheet

General Catalog

VRF-HVRF Systems Catalogue