Products /  HIU's

HIU's

The Heat Interface Unit (HIU) is a complete package comprising all components mounted on a frame, factory assembled and tested. Versatile Heating, Cooling & Ventilation have partnered exclusively with Herz to bring quality, European HIUs to the Irish market. 

 
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Guildford Indirect HIU

The Guildford Indirect HIU (Heat Interface Unit) from Herz is suitable for all community schemes and enables LTHW from a central plant to provide heating and DHWS to each dwelling with complete hydraulic separation between the LTHW primary and secondary heating and DHWS systems.

The HIU is a complete package comprising of all components mounted on a frame, factory assembled and tested.

a) Residents Heating System

The primary flow to the heating system heat exchanger is controlled by a two port on/off actuated valve linked to a programmable room thermostat (Herz 3 F799 17). This valve will close when the room temperature setting has been achieved or when the heating system is not in use. A fixed spring differential pressure control valve is fitted across the primary flow and return circuits on each HIU to protect the control valves from excessive DP.

The secondary heating circuit is provided with an expansion vessel and secondary domestic heating pump which varies the system flow rate automatically based on demand.

b) Domestic Hot Water (DHW)

Domestic hot water is generated via the DHW heat exchanger mounted in the HIU and provides instantaneous hot water on demand.

DHW temperature and primary flow rate through the heat exchanger is controlled via the Pressure temperature control valve, which is temperature compensated and requires no auxiliary power to operate.

 

When a hot water tap is opened the drop in pressure in the hot water pipe will open the 4 port pressure temperature control valve which in turn will allow primary hot water into the heat exchanger.

When the hot water demand ceases the pressure temperature control valve will immediately stop the primary flow into the heat exchanger. Therefore there is no drain on the primary heating when there is no demand, so no “extra energy usage” when residents are on holiday for example.

A tempering valve is provided to counter the effect of temperature overshoot caused when a hot tap is closed and opened again in a short space of time, this also ensures a stable output temperature.

A thermostatic “summer” bypass valve is fitted to maintain a minimum primary temperature when the space heating is not in use. This provides a quick DHW response and avoids unnecessary energy usage.

The Guildford HIU has the option to have a stand-off bracket installed to enable the services to be connected from the top of the unit. The top entry stand-off bracket enables any combination of services to be piped from above or below the HIU. Pre-formed, pre-insulated pipes, complete with all connections, are available to provide full flexibility.

 Features & Benefits:

  • Instantaneous hot water and space heating to properties

  • Twin heat exchangers provide hydraulic separation

  • Thermostatic hot water temperature control

  • Tempering valve to prevent risk of scalding

  • Differential Pressure Control Valve

  • Insulated back board, secondary heating heat exchanger & heating pipework

  • Insulated lockable cover with viewing window allows meter reading without casing removal

  • Low primary return temperature maximises system efficiency

  • Optional primary flushing bypass available

  • Option for heat meter (110mm Spool piece provided as standard)

  • Option for water meter (110mm Spool piece provided as standard)

  • 18mm stainless steel pipe work

  • Full WRAS approval

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Dublin Indirect HIU

Pressure Temperature Control Valve

As a hot water tap is opened the pressure temperature control valve reacts to the difference in pressure via a diaphragm and opens allowing the cold and primary heating water to flow through the heat exchanger. At the same time, a hot water priority valv e closes the primary feed to the secondary heat exchanger, thus ensuring maximum flow is available at the domestic heat exchanger. In order to prolong the life of the DHW heat exchanger and prevent lime scale build up , the temperature of the domestic hot water is controlled by a thermostat fitted to the pressure temperature control valve . Using an immersion sensor, this thermostat controls the temperature of the hot water that exits the heat exchanger and regulates the pressure temperature control valve thus maximising the energy efficiency of both the HIU and the primary system.

Zone Valve

The primary flow to the heating system heat exchanger is controlled by a two port on/off actuated valve linked to a programmable room thermostat. This valve will close when the room temperature setting has been achieved or when the heating system is not in use.

Summer Bypass Valve

The ”Summer bypass” valve utilises a return temperature limiter head fitted to a thermostatic valve installed in a bypass between the primary flow and return pipework within the HIU. This maintains a minimum primary temperature when the space heating is not in use.

First Fix Rail

The First Fix Rail is a pre-assembled unit fitted with all the isolation ball valves required for the various circuits installed within the HIU. The unit is installed at first fix and allows shell and core pipework to be completed without the HIU being fitted. The first fix rail ball valves are fitted with drain valves with integral test points on the primary flow and return to facilitate draining and to aid additional temperature or pressure measurement if required. The first fix rail with ball valves also allows maintenance to be carried out on the HIU as the main unit can be removed easily.

Features & Benefits:

  • Instantaneous hot water and space heating to properties

  • Twin heat exchangers provide hydraulic separation

  • Thermostatic hot water temperature control ”Summer bypass” valve

  • First Fix pre-mounting rail Low primary return temperature maximises system efficiency

  • Suitable for radiators or underfloor heating

  • Option for heat meter (110mm Spool piece provided as standard)

  • Viewing window allows meter reading without casing removal 110mm

  • Spool piece provided for water meter

  • WRAS approved products utilised where required

  • 18mm stainless steel pipe work

 

Functions:

a) Residents Heating System

The primary flow to the heating system heat exchanger is controlled by a two port on/off actuated valve linked to a programmable room thermostat (Herz 3 F799 17 ) . This valve will close when the room temperature setting has been achieved or when the heating system is not in use. A differential pressure control valve should be fitted on each HIU or across the primary flow and return circuits in the distribution pipework or to protect the control valves from excessive DP. The secondary heating circuit is provide d with an expansion vessel and secondary domestic heating pump which varies the system flow rate automatically based on demand.

b) Domestic Hot Water (DHW)

Domestic Hot Water (DHW) is generated via the DHW heat exchanger mounted in the HIU and provides instantaneous hot water on demand. DHW flow rate and temperature is controlled via the Pressure temperature control valve which is temperature compensated and requires no auxiliary power to operate. When a hot water tap is opened the drop in pressure in the hot water pipe will open the 4 port pressure temperature control valve which in turn will allow primary hot water into the heat exchanger. When the hot water demand ceases the pressure temperature control valve will immediately stop the primary flow into the heat exchanger. Therefore there is no drain on the primary heating when there is no demand, so no “extra energy usage” when residents are away on holiday, for example. A thermostatic “summer” bypass valve is fitted to maintain a minimum primary temperature when the space heating is not in use. This provides a quick DHW response and avoids unnecessary energy usage.

Energy Metering

As an option the HIU can be provided with a built in battery powered energy meter mounted in the primary heating return pipe. The meter will measure flow using the ultrasonic principle with an accuracy complying with EN1434 and MID in Class 2 with dynamic range of 1:250 (qi:qp) The heat meter has options for pulse, M bus or radio to allow remote reading with hand held scanner, drive by or remotely via GPRS. All necessary system hardware and software is available on request. If a cold water meter is fitted this can be pulse linked to the energy meter. The heat calculator will display energy usage in kW hours . Battery life approximately 12 years.

System Balancing

High differential pressures could affect the performance of some components in the HIU and in particular cause temperature spikes in the hot water. Excessive differential pressures can also cause noise and reduce the lifetime of components within the HIU. We would recommend that DPCV should be installed on each HIU to protect the components from excessive differential pressures and to control flow. If this option is not utilised then differential pressure control valves must be fitted at branches/floors to stabilise pressures and temperatures.

 
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Oxford HIU

The Oxford DHW from Herz is the only HIU is suitable for all community schemes and enables LTHW from a central plant to provide DHWS to each dwelling with complete hydraulic separation between the LTHW primary and the DHW systems.

The HIU is a complete package comprising of all components mounted on a frame, factory assembled and tested.

Functions

Domestic hot water is generated via the DHW heat exchanger mounted in the HIU and provides instantaneous hot water on demand.

The temperature of the DHW is controlled by a thermostatic head with an immersion sensor, this head controls the temperature of the hot water that exits the heat exchanger and regulates the primary water flowrate.

When a hot water tap is opened the drop in pressure in the hot water pipe will open the 4 port pressure temperature control valve which in turn will allow primary hot water into the heat exchanger.

When the hot water demand ceases the pressure temperature control valve will immediately stop the primary flow into the heat exchanger. Therefore there is no drain on the primary heating when there is no demand, so no “extra energy usage” when residents are on holiday for example.

A thermostatic circulation bypass valve is fitted to maintain a minimum primary temperature when there is no demand for hot water and the heat exchanger is not in use. This provides a quick DHW response and avoids unnecessary energy usage for the occupier.

Features & Benefits:

  • Instantaneous hot water to properties

  • Low primary return temperature maximises system efficiency

  • Fully insulated cover and back board

  • Option for heat meter (110mm Spool piece provided as standard)

  • Option for water meter (110mm Spool piece provided as standard)

  • WRAS approved products utilised where required

  • 18mm stainless steel pipe work

  • Lockable cover with security fixing screw

  • Dual orientation for ease of connection

  • Optional ball valve cover available if required

 
 

Ecosse HIU

The Ecosse HIU from Herz is suitable for all community heating schemes and enables LTHW from a central plant to provide heating and DHWS (if required) to each dwelling with complete hydraulic separation between the LTHW primary and secondary heating and storage type DHW systems.

The HIU has a single heat exchanger providing heated water. The heating supply from the HIU can be utilised for space heating and DHW cylinder storage in an “S Plan” configuration if required, or alternatively can be used for single use, either for space heating or for DHW storage systems.

The HIU is a complete package comprising of all components mounted on a frame, factory assembled and tested.

Functions:

a) Primary Heating

The primary heating temperature is controlled by a Herz temperature limiting valve located in the return.

A Herz fixed spring differential pressure control valve is also fitted as an integral part of the HIU to protect the temperature limiting valve and govern flow rate.

b) Residents Heating System

If the HIU is only supplying the space heating, then the primary flow to the heating system heat exchanger is controlled by a two port on/off actuated valve linked to a programmable room thermostat (Herz 3 F799 17). This valve will close when the room temperature setting has been achieved or when the heating system is not in use.

The secondary heating circuit is provided with an expansion vessel and secondary domestic heating pump which varies the system flow rate automatically based on demand.

c) Residents Hot Water (DHW)

If a hot water storage cylinder is being used, the common heating circuit from the secondary side of the heat exchanger divides and supplies the apartment heating system utilising a zone valve (supplied by others) which is controlled by a room thermostat. The common secondary heating circuit also provides primary heating to a hot water storage cylinder (not supplied). This circuit is controlled via a zone valve and cylinder thermostat (not supplied) which opens the zone valve when the cylinder temperature begins to drop.

Both DHW and Secondary heating will work to the dictates of a central heating programmer.

Features & Benefits:

  • Single heat exchanger provides hydraulic separation

  • Low primary return temperature maximises system efficiency

  • ”S type” configuration for secondary heating and hot water storage systems if required

  • Differential pressure control valve across the primary

  • Zone valve to ensure that water circulates through the heat exchanger only when there is a demand

  • First fix rail to aid easy installation

  • Top and bottom connections available

  • Suitable for radiators or under floor heating systems

  • Insulated heat exchanger

  • Insulated pipework within the HIU

  • Option for heat meter (110mm Spool piece provided as standard)

  • Viewing window allows meter reading without casing removal

  • 18mm stainless steel pipe work

York HIU

The York Direct HIU from Herz is suitable for all community schemes and enables LTHW from a central plant to provide heating and DHWS to each dwelling with complete hydraulic separation between the LTHW primary and DHWS system.

The HIU is a complete package comprising of all components mounted on a frame, factory assembled and tested.

Functions:

a) Residents Heating System

The primary flow to the secondary heating system is controlled by an integrated fixed spring differential pressure control valve with on/off actuated zone valve linked to a programmable room thermostat (Herz 3 F799 17). This valve will close when the room temperature setting has been achieved or when the heating system is not in use. The differential pressure controller is fitted across the secondary flow and return circuit on each HIU to ensure that the delta t is maintained to maximise system efficiency and the return temperature.

b)  Residents Hot Water (DHW)

Domestic hot water is generated via the DHW heat exchanger mounted in the HIU and provides instantaneous hot water on demand.

DHW temperature is controlled by a thermostat fitted to a thermostatic control valve. Using an immersion sensor, this thermostat controls the temperature of the hot water that exits the heat exchanger and regulates the thermostatic control valve thus maximising the energy efficiency of both the HIU and the primary system.

When a hot water tap is opened the drop in pressure in the hot water pipe will open the 4 port pressure temperature control valve which in turn will allow primary hot water into the heat exchanger.

When the hot water demand ceases the pressure temperature control valve will immediately stop the primary flow into the heat exchanger. Therefore there is no drain on the primary heating when there is no demand, so no extra energy usage when residents are on holiday for example.

A thermostatic summer bypass valve is fitted to maintain a minimum primary temperature when the space heating is not in use. This provides a quick DHW response and avoids unnecessary energy usage.

c) Residents Hot Water (DHW)

If a hot water storage cylinder is being used, the common heating circuit from the secondary side of the heat exchanger divides and supplies the apartment heating system utilising a zone valve (supplied by others) which is controlled by a room thermostat. The common secondary heating circuit also provides primary heating to a hot water storage cylinder (not supplied). This circuit is controlled via a zone valve and cylinder thermostat (not supplied) which opens the zone valve when the cylinder temperature begins to drop.

Both DHW and Secondary heating will work to the dictates of a central heating programmer.

Features & Benefits:

  • Single heat exchanger provides hydraulic separation

  • Low primary return temperature maximises system efficiency

  • ”S type” configuration for secondary heating and hot water storage systems if required

  • Differential pressure control valve across the primary

  • Zone valve to ensure that water circulates through the heat exchanger only when there is a demand

  • First fix rail to aid easy installation

  • Top and bottom connections available

  • Suitable for radiators or under floor heating systems

  • Insulated heat exchanger

  • Insulated pipework within the HIU

  • Option for heat meter (110mm Spool piece provided as standard)

  • Viewing window allows meter reading without casing removal

  • 18mm stainless steel pipe work

 

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Versatile Group
Beechmount Home Park,
Navan, Co. Meath, C15 WR60

T: +353 (0)46 9029444
F: +353 (0)46 9027704
E: info@versatile.ie

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