Polyvalent heat pumps (4 pipes)

EUROVENT Certified - Made in Italy

Multifunctional units dedicated to 2, 4 and 6 pipes systems

RHOSS EXP-Polyvalent system is the intelligent solution to air conditioning requirements in plants where the heating demand is simultaneously or independently combined with a cooling request.

The units adapt well to various types of systems, thereby guaranteeing unique efficiency and versatility.

The units are designed to reach energy efficiency at high levels and guarantee fields of work that allow operation throughout the year.

Sub Products Heading



Air cooled

  • From 17kW to 698kW (EUROVENT conditions)

Water cooled

  • From 5kW to 740kW (EUROVENT conditions)


  • Scroll

  • Inverter Scroll

  • Screw

Fans (Axial & Centrifugal)

  • AC fans with speed controller

  • EC fans

  • High static pressure EC Fans (Ductable air)


  • R410A, R134A, R454B


  • Additional partial heat heat recovery (Desuperheater) 6 pipes systems

  • High ambient temperature performance

  • Plate heat exchangers & Shell & Tube heat exchangers

  • Fully hydronic kits (Single pump, double pumps, expansion tank, buffer tank) both circuits (cooling and heating)

  • Variable primary flow by RHOSS

  • And much more… (Low noise level, noise reduction software, inbuilt master/slave, HLI…)

2, 4 or 6 pipes system?
2, 4 or 6 pipes system?

What is a 2 (two) pipes system?

In this plant, there is the need for space cooling in summer and for space heating in the winter season (typical application with terminal units, e.g. fan coils). In addition, there is a simultaneous request for DHW all year round. Sometimes there is also the request for hot water at a higher temperature.

Typical units used in this system are traditional chillers or heat pumps with the integration of a HR (available during summer only) and a boiler.

What is a 4 (four) pipes system?

In this type of plant, there are requests for space cooling and space heating all year round (typical application with hydronic terminals, e.g. fan coils with double coils). In this case, the thermal loads to satisfy can be simultaneous and opposite. Sometimes there is also the request of hot water at a higher temperature (6 PIPES).

Using a chiller and a boiler, or a chiller + HR and a boiler (to limit the use of the boiler in summer), or a heat pump + HR and a boiler are the simplest ways to build this system.

What is a 6 (six) pipes system? Hot water up to 70°C

This is a 4 pipes system with an additional request for hot water at a higher temperature (6 PIPES). As a result of the option to manage 6 pipes systems, WinPOWER EXP units can produce water up to 70°C in the dedicated heat exchanger.

RHOSS EXP - How it works
RHOSS EXP - How it works

EXP is a Multipurpose ecological system designed by RHOSS to:

Meet the simultaneous or independent requests for hot and chilled water.

  • Optimize energy consumptions.

  • Make running easier.

  • Avoid or reduce the use of fossil fuels.

  • Increase overall system efficiency.

  • … With one unit

Is a reversible Heat Pump a 4 pipes unit? Don't be fooled!

The straight and short answer to this is NO!

This is one of the most common confusions in the Australian HVAC&R industry, a reversible heat pump is a 2 pipes design to deliver cooling during summer and heating during winter.

The confusion gets even bigger once a partial heat recovery (Desuperheater) is added to the heat pump, because physically the heat pump with the inclusion of the new heat exchanger (heat recovery) now has 4 pipes to be connected.

The main difference is that in order to have heating, it is required demand for cooling. Removing, the advantage of simultaneous or independent cooling or heating demand.

But, be careful, the datasheet looks very similar in a heat pump with heat recovery to a 4 pipes polyvalent unit.

RHOSS Efficiency advantage
RHOSS Efficiency advantage

RHOSS EXP - High Energy Efficiency

Especially in the combined operation mode (TER index)

TER = (cooling capacity+heating capacity) / Power input


RHOSS is a company specialised in the design and manufacture of products and systems for air conditioning and air handling.

Founded in 1968, it immediately became the leader in the sector of steel boilers for domestic heating.

It entered the world of air-conditioning in 1971 with the production of fan coils and subsequently with cooling units.

For more than 50 years, RHOSS has been a guarantee for innovation, quality and top level service. This is what makes us an ideal partner for HVAC (Heating, Ventilation and Air Conditioning) system specialists.

RHOSS growth and development is an evolution that combines investments and projects in order to make the company a point of reference also for international markets.

Our renewal has followed market development and customer needs, in particular offering highly efficient products and systems that are in line with the requirements of the most modern Green Buildings.



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