YGHP combined HIU CIU offer all the advantages of having the HIU & CIU in one position, but as they do not share the same thermal cover we are able to minimize the risk of condense effecting performance of both units.

The YGHP combined heating, hot water, and cooling interface units are designed to deliver complete indoor climate control in a single, compact solution.

By integrating all essential utilities into one unit, YGHP systems eliminate the need for multiple separate components, freeing up valuable space and simplifying system design—ideal for modern homes, apartments, and commercial developments where efficiency and footprint matter.

With a streamlined, all-in-one configuration, installation is faster and more straightforward, reducing labour time and associated costs. Fewer connections and components also mean a cleaner, more reliable setup with less risk of installation errors. For property developers and contractors, this translates into smoother project delivery and improved consistency across builds.

Maintenance is equally simplified. Having heating, hot water, and cooling consolidated into a single interface unit allows for easier access, quicker servicing, and reduced downtime. This not only lowers ongoing maintenance costs but also ensures long-term system performance and reliability.

Ultimately, YGHP interface units provide a smart, space-saving solution that enhances efficiency, reduces complexity, and delivers year-round comfort—all from one integrated system

Combined, compact design to save space.

Latest SWEP plate heat exchanger offering exceptional performance.

Flexible capacities to suit all project specifications.

Stainless steel pipework to ensure high performance and longevity.

EPP thermal casing to ensure minimum heat losses and maximum heat efficiency.

Each combined unit is equipped with 2 WILO circulation pumps. 1 for the CIU and 1 for the HIU.

As the first high-efficiency pump in the world, the WILO defined energy efficiency class A for stand-alone circulators, thereby setting a new standard.

WILO extended this product technology towards new pump ranges especially for requirements of the OEM industry.

he DPCV operates using a spring-loaded diaphragm mechanism:

  • The valve has an internal diaphragm connected to a spring calibrated to a specific pressure setting.
  • Pressure from the flow and return sides of the circuit is transmitted via impulse tubes or internal channels to opposite sides of the diaphragm.
  • When the differential pressure exceeds the setpoint, the valve modulates towards a closed position, restricting flow.
  • When the differential pressure falls below the setpoint, the valve opens further to allow increased flow.

This continuous modulation maintains a near-constant pressure differential across the HIU or a specific sub-circuit within it.

The combined unit is equipped with two expansion vessels to maintain constant pressure in the system.

The expansion vessels are made from a rubber diaphragm fixed membrane and according to the standards established by PED 2014/68/UE and DIN EN 13831 regulations.

3 bar safety relief valve within a Heat Interface Unit (HIU) is a critical protective component designed to safeguard the sealed heating circuit from overpressure conditions. Its primary function is to automatically discharge water when system pressure exceeds a predetermined threshold—typically 3 bar—thereby preventing damage to internal components, pipework, and connected emitters.

To connect the combined unit and the piping system of apartment, mounting plates are used. These plates have 10 ball valves and a flushing by-pass.

Each secured on a galvanized steel plate, ball valves are connected with G ¾” male thread connections.

Flushing by-pass enables the flushing and venting of the system before commissioning the combined unit.

Each combined unit is equipped with multiple plate heat exchangers to exchange heat between supply and the combined unit.

In the combined unit, the heat exchangers are optimized asymmetric plate geometries that combine extraordinary thermal efficiency. The heat exchangers have been selected to satisfy the requirements on the heat load and the flow rate of the system.

Flow Limitation (Balancing Function)

The control valve is preset to a maximum design flow rate. Regardless of pressure fluctuations in the system, it ensures that:

  • The flow never exceeds the design value
  • Each CIU or terminal receives its correct share of cooling capacity

This eliminates the need for separate commissioning valves and reduces commissioning time.

Differential Pressure Independence

Unlike conventional control valves, the control valve maintains a constant flow characteristic independent of system pressure variations.

This is crucial because:

  • In variable flow systems, pressure changes occur as other valves open/close.
  • Without pressure independence, flow would fluctuate, causing unstable cooling.

Pressure-independent valves ensure stable hydronic balance at both full and part load conditions.

Modulating Control (with Actuator)

  • It modulates flow based on cooling demand
  • Maintains precise supply temperature to the terminal units
  • Can operate with linear or equal-percentage characteristics depending on actuator setup

All YGHP combined units come equipped with state of the art thermal casing, made from EPP or Expanded Polypropylene.

This ensures that the unit is reaching its maximum thermal potential and reducing heat-loss to a minimum.

The shock arrestor is fitted to stop water hammer and absorb any pressure from water to avoid pipes banging/vibrating throughout the hydraulic action.

How It Works Within a YGHP HIU:

1. Demand for Heat

  • A room thermostat or programmable controller detects that the room temperature is below the setpoint.
  • It sends an electrical signal (usually 230V or 24V) to the HIU’s control system.

2. Signal to the Actuator

  • The HIU controller energises the heating actuator.
  • This signal tells the actuator to open the control valve.

3. Valve Opening

  • The actuator motor turns, driving gears that push or rotate the valve stem.
  • The valve opens, allowing primary hot water from the heat network to flow through the HIU.

4. Heat Transfer

  • Hot water passes through a plate heat exchanger inside the HIU.
  • Heat is transferred to the secondary circuit (the dwelling’s heating system).
  • The primary and secondary water never mix—only heat is exchanged.

5. System Circulation

  • Heated water is circulated through the radiators via a pump.
  • The HIU may modulate flow depending on demand (in more advanced systems).

6. Satisfied Demand

  • Once the room reaches the desired temperature:
    • The thermostat cuts the signal.
    • The actuator de-energises.

7. Valve Closing

  • A spring return (or motor reversal in some designs) closes the valve.
  • Flow of hot water stops, preventing overheating and saving energy.