A Heat Interface Unit (HIU) like the HIPER 2 is essential for efficient heating and hot water supply in multi-dwelling buildings. Regular maintenance and checks are crucial to ensure optimal performance and to diagnose any potential issues early. Here’s a comprehensive checklist to follow before diagnosing any faults or issues:
By following this checklist, you can ensure that your HIPER 2 HIU is operating efficiently, and any potential issues are identified early. Regular maintenance not only extends the life of the unit but also ensures consistent and reliable heating and hot water supply.
Variable system conditions present challenges that the Hiper HIU PID control system meet by providing stability and rapid reaction to changes in supply and demand. The PICV (control valve) regulation delivers the design flow rate without affecting the modulating travel of the valve, so full authority is available throughout the full scope of the modulation. It is controlled by the electronic PID controller with constant monitoring from temperature and flow sensors at all critical flow and return paths. Key is control of the DHW demand, even at low flow, and still maintaining low return temperatures.
A proportional–integral–derivative controller (PID) continuously calculates an error value as the difference between a set point and a measured process variable and applies a correction based on the ‘proportional, integral and derivative’ values. In practical terms it automatically applies accurate and responsive correction to a control function, much like cruise control on a car. The PID algorithm maintains the set point without delay or overshoot, by controlling the stepper motor of the PICV actuator.
Having one modulating valve with control of pressure differential means that it must adapt to the different demands of either hot water or central heating which is not possible with a thermostatic valve. The Hiper HIU electronically maintains the temperature set points and limits the flowrates to presets within the controller.
In the Hiper HIU ppressure drop is created by the primary control valve and not the heat exchanger itself. For a low secondary flow, the primary valve is only going to open a small amount (10-15%). This will create a very high pressure drop from the valve itself. The pressure drops over the heat exchanger will be low. When the flow rate is high, this causes the primary valve to open wider or fully, and then decreasing the pressure drop over this valve significantly. In Hiper II the total pressure drop decreases as the primary flow increases. The maximum pressure differential across the PICV is 400 kPa giving a good scope for consultants to size pipes according even for the closest connections to the pump.
Delivering DHW at the taps without long waiting times is down to the response time of the HIU and the plumbing design of the pipework in the home. The response time set in the BESA test regime for HIU’s sets the standard as the DHW temperature leaving the HIU must reach 45oC in 15 seconds or less. It is important in any HIU manual bypasses are not used, and the HIU should have a means of controlling the return temperature through any ‘Keep Warm’ functions to prevent excessive temperatures back to the Boiler Plant Room.
The Hiper HIU in enters its Keep Warm mode after a preset time, which the installer sets on commissioning, which can be on or off. Factory set on.
The time range for initiating this function is between 5 minutes and 24 hours.
The primary return temperature limit is set at 39C, so the keep warm function is temperature controlled. In some circumstances end users will not want or need this function, but the choice is there. When the Hiper HIU then enters Keep Warm mode, after it’s elected time to activate, it maintains heat in the PHE by temperature control of the plate and limiting the temperature of the primary return. The average flow over the 8 hour tests by BESA was 4.5 Ltrs/hr
These have been measured and calculated in the BESA test regime. This is the VWART (Volume Weighted Average Return Temperature) calculation and is a good guide to the HIU characteristics. VWART calculations are provided for DHW, Space Heating and Standby operational modes. Then an overall average figure is stated for each tested HIU.
Heating takes up most of the operational mode, either by radiators or by underfloor heating, and returns the highest temperatures to the network and plant. It is very important therefore that the circuit is balanced and uses the most effective means of control, and no circuits left ‘open’. Underfloor heating by nature of its lower operating temperatures is particularly suited to HIUs.
Hiper HIU by nature of being electronically controlled has an ‘optimised heating’ feature. Temperature on both flow and return are monitored by the controller, and as the room temperature gets close to the comfort level of the room, the controller then reduces the temperature to the space heating circuit, preventing overshoot of room temperature and maintaining lowest return temperatures to the network and plant.
So the important trade off against the Space Heating VWART is the DHW and Standby modes.
Standby, or ‘Keep warm’ is temperature controlled and controls and limits the return temperature to 40C (a programmable function).
Low DHW return temperature is provided by the PHE. Hiper II uses a ‘asymmetric’ design gives the highest thermal performance with low pressure drop.
| HIGH TEMPERTURE TEST RESULTS | °C |
|---|---|
| DHW VWART | 15 |
| Standby VWART | 38 |
| Space Heating VWART | 41 |
| Overall Result | 28 |
| LOW TEMPERTURE TEST RESULTS | °C |
|---|---|
| DHW VWART | 16 |
| Standby VWART | 38 |
| Space Heating VWART | 35 |
| Overall Result | 29 |
BESA Test Regime
Calculation of the annual Volume Weighted Return Temperature (VWART) from the HIU, with this being a composite of estimations of the annual volume-weighted return temperatures for domestic hot water, space heating and keep-warm functions.
It is the recording of energy consumption. The device comprises of a flow sensor, two fixed connected temperature sensors and a calculator that calculates energy consumption using the volume and temperature difference. This can then be manually read from the display on the meter calculator, but more likely connected to a billing provider by remote reading Mbus connection. The meter should contain a permanent memory which stores the heat consumption data. The meter calculator can also display the primary flow value.
Mbus is Meter bus, and is the European standard (EN 13757-2 and EN13757-3) for the remote reading of heat, water, gas or electricity. Mbus communication is by simple two wire connection, and the ‘billing provider can monitor the heat being used and bill the tenant for the heat consumed.
Modbus is a communication protocol developed by Modicon systems. In simple terms. A method used for transmitting information over serial lines between electronic devices. The Modbus Master is the device which requests information and Modbus Slaves supply information. Modbus remains the most widely available protocol for connecting industrial devices
It has become very common and is used widely by many manufacturers throughout various industries. Modbus is used typically to transmit signals from instrumentation and control devices back to a main controller or data gathering system.
Modbus protocol is defined as a master/slave protocol, meaning a device operating as a master will poll one or more devices operating as a slave. This means a slave device cannot volunteer information; it must wait to be asked for it. The master will write data to a slave device’s registers and read data from a slave device’s registers. A register address or register reference is always in the context of the slave’s registers.
The most used form of Modbus protocol is RTU over RS-485. Modbus RTU is a relatively simple serial protocol that can be transmitted via traditional UART technology. Data is transmitted in 8-bit bytes, one bit at a time, at baud rates ranging from 1200 bits per second (baud) to 115200 bits per second. Most Modbus RTU devices only support speeds up to 38400 bits per second.
A Modbus RTU network has one Master and one or more Slaves. Each slave has a unique 8-bit device address or unit number. Packets sent by the master include the address of the slave the message is intended for. The slave must respond only if its address is recognised and must respond within a certain time or the master will call it a “no response” error.
The Hiper II electronic controller is modbus ready for connection.
Payment of heat to be used in advance. For installations where the landlord of the properties has fitted a metering system that enables a scheme where the tenant pays for heat by pre-payment, the HIU has the capability to shut down the supply of heat when payment agreements have not been met. The HIU Controller should have an auxiliary connection terminal that facilitates this option.
It means that the facility and capability to shut down the HIU when the billing system signals that that tenant has used all their credit. Hiper II Heat Interface Unit has connections for volt free connections for immediate connection, no other valve required for shutting off supplies when the client is ‘out of credit’.
To connect to a prepayment billing system simply go into the installer setting and turn ‘ON’ Prepayment function, and connect the billing system cable to the connection in the controller.
The controller shuts down the PICV completely and also cancels out keep warm function to prevent ‘credit minus’ on billing.
The HIU needs no other valves to shut down when the billing is out of credit, saving cost on purchase of a motorised valve capable of closing against pressure differentials in the system and installation time.
The billing system working in conjunction with the heat meter selected by the consultant or energy provider, is usually volt free, but if is 230 volt signal then an accessory relay box is available. Consult the billing provider for this information.
In the BESA test without insulation on any part of the HIU, the average heat load measured on the primary side was 42W. Insulation of the casing, backplate and PHE is now standard on our production HIU and substantially lower heat load figures are to announced subject to independent testing. Why is the figure so low without insulation? Because using hydro blocks and the Hiper design reduces pipework to a bare minimum.
Insulation Properties –
Pulse Width Modulation. The pump speed can be controlled by the HIU.
Factory setting on Hiper II HIU is OFF.
Set PWM on, and connect the additional PWM cable to the pump. In operation,the speed decreases when the PWM value increases. If PWM equals 0, the pump runs at maximum speed. At high PWM signal percentages (duty cycles), a hysteresis calculation prevents the pump from starting and stopping if the input signal fluctuates.
This can be programmed in the controller installer menu at parameter 24.
Parameter 24 setting options are from 1 to 99 (1 = PWM 1% to 99 = Max speed)
The controller reads the speed of the pump, and generates an error code if it doesn’t rotate when in heating mode or when the pump is switched on manually in parameter 25 (test mode).
There is no issue with regards to the potential of pumping against closed valves occasionally. If a UPM3 Auto is used and run in CP mode it will automatically detect this and slow down until the valve opens and flow is required.
Hiper II can be configured to two bands of set heating temperatures, a higher band for radiator heating, and a lower band for underfloor heating (UFH). On first power up, this choice has to be made by the installer, but can also be re-set in the installer level of programming the parameters.
For drying newly laid screed in UFH installations there is a European standard EN1264-4 part 4.4.1.
This drying operation is different for different screeds.
Note that for all screed materials the manufacturer’s specifications should be followed. The Slab drying function in the Hiper II HIU follows this requirement.
The Slab drying function can be initiated during first power up (step 4a) of the controller or by setting on in parameter 94, change parameter setting from OFF to ON.
When it is activated is will deliver a flow temperature limited to 25C for 3 days, before raising the temperature to the UFH set temperature for 4 days before finishing and returning to standby mode. While in ‘slab drying’ mode the screen will show hours and minutes in operation and temperature of the flow to the floors.
The HIU will maintain the temperatures in the UFH system by its controller. Automatic diagnostics protect the UFH from high temperatures should the temperature sensors fail.
HIUs being remotely monitored so giving the operator or maintenance service engineers has been the long term objective for making an interface unit that is electronically controlled rather than thermostatic. Electronics enable monitoring, and with the information that the electronic controller uses to control stable operating temperatures and employ self-diagnostics the network operator is able to manage the efficient operation of the network and each interface unit remotely.
A manufacturer and billing services provider are different entities, so reliable partnerships must be forged. Also, some operators and customers may feel that losing the option of using billing services of their choice a limiting factor and want to have the option of flexibility so that is dissatisfied with the chosen service in the future change. Having the option to do that is important in the selection of service providers.
The Inta iPulse packages allow flexibility in choice and provide a FULL range of services from support in HIU selection through all the stages of sales, installation, commissioning, warranty support and servicing to the annual customer billing for heat used and monitoring of the units and network ultimate efficiency.
Hiper II is equipment with Modbus communications to enable the addition of centralised management packages.
Centralised Management Package (CMP) organised by Inta iPulse.
HIU with modbus communications capability and operational information gathering.
This information is processed into regular summaries and is linked to the billing provider and the Inta Service Desk.
CMP Hardware
The ‘add on’ electronics sealed box sold by Inta. The installer wires this into the Hiper HIU, and the box is wall mounted.
Billing Package.
Provided by the ’Billing Provider’ and the only connection is to the Heat Meter, not the HIU modbus.
Service Plan.
Inta has connection to each HIU on the plan and monitors for Fault ’alarms’. Alarms can be automatically copied and linked to service engineer sub-contractors. Inta maintains a history of faults, remedial actions and value of charges made by Service engineers. Warranty work can be reviewed and compared with back charges to suppliers.
Commissioning Plan
Option to use Inta appointed commissioning engineers. Inta will quote and the installer can choose this option or do this themselves or appoint another sub-contractor. On completion the HIU must be registered with Inta.
Service Desk
Set up as a portal to communicate between Inta and all installed HIU linked & contracted to the Service Plan.
Monitoring Plan
The contract between the Client and the Billing Provider to allow the client to monitor the HIU’s and the Energy Efficiency of the building and homes that are listed on the Monitoring Plan contract and have purchased the HIU and CMP hardware from Inta.
The Client
Is the owner of the Service Plan as sold by Inta, and/or the owner of Monitoring plan as sold by the Billing Provider.
The Billing Provider
Supplies the CMP Hardware to Inta at an agreed price, and provides the Billing Package and the Monitoring Package to the Client.
Inta provide HIU and CMP (iPulse) sales to the installer or Merchant, sales of the Service Plan to the client. Maintains the service plan to the client during the warranty period of 3 years.
The additional electronics box that provides the flow of information between the HIU the Gateway which provides the internet connection for the Monitoring Plan. This will take the form of a small plastic box which will be mounted outside the HIU, possibly on a wall mounting bracket. This box will be wired to the Modbus connection in the controller and also linked to Heat Meter mBus to read primary flow rates.
The distribution of heat through a network of pipes from a heat source remote from all the homes and premises that it serves.
District heating networks in some cases can cover large areas and service multiple buildings and homes. They can be added to later and linked to other schemes to form an even larger network.
District Heating heat networks deliver cost effective, low carbon heat, in the form of hot water or steam, from the point of generation (usually an energy centre) to the end user through a network of insulated pipes.
Heat Networks vary in size and length, carrying heat just a few hundred metres between homes and flats, to several kilometres supplying entire communities and industrial areas. The distance a network can reach is also easily extended by simply adding more providers of heat, or ‘heat sources’, along the way.
Heat networks can be supplied by a diverse range of sources including:
The development of heat networks will contribute to the production of decarbonised heat for both domestic and commercial use. Low temperature networks will be the result of current and future changes to heat network regulation. Net-zero carbon targets are now encouraging suppliers to harness energy from renewables and industrial by-products.
It is important that the M&E consultants and Developers understand where the key lines of responsibility ownership lie. Some energy centres may supply many different buildings and clear understanding of ownership is important and should ensure that the responsibility for maintenance and metering understood by all involved. Demarcation is important for small community heating schemes as well as larger networks.
Centralised plantrooms in large buildings and separate substations for smaller buildings are recommended. The plate heat exchangers in these plantrooms and substations creates clear demarcation lines that separate the main network from each individual building or estate, and providing a pressure break.
Pressure breaks in communal heating plant rooms and substations ensure that taller buildings do not affect the pressure other parts of the network.
The design engineer will be looking to achieve the most efficient source of heat that is practical for each individual project. Gas condensing boilers, multi-stage boilers, heat pumps, and to a lesser degree combined heat and power (CHP) or biomass boilers. Other low carbon methods such as solar thermal are also to be considered as secondary heat sources. Larger systems can tap into waste heat recovery projects.
Usually a twin pump set for circulating water and heat from the heat source to the buffer tank at constant speed / flow. The pump will be moving heat from the heat source and into the buffer as required.
The purpose of the buffer vessel is to provide heat to meet peaks of maximum demand which occur over short periods, storing heat for later use and supplementing the heat source when demand is high. Stored heat is immediately available without the heat source needing to get up to temperature. The buffer should be sized correctly to match the load demand with consideration to the heat source, building construction, and even the number of people that possibly can create a demand during peak demand times, usually morning and evening.
Circulates heat around the network of pipes comprised by the risers (vertical) and lateral pipes (horizontal pipe work). A variable speed circulating pump capable of efficiently operating at operating at part load. The pump should be sized to meet speed and flow design requirements and be controlled so that there is always sufficient pressure and flow available to feed all the HIUs in the network equally.
Provision for venting air from the Risers, Provision for maintaining circulation when all control valves in the HIUs are closed. Automatic air venting and differential bypass control.
Building systems are designed to meet peak heating demand and ignore working at part load. Designing a system to peak outputs and factoring in a margin for additional capacity to guarantee meeting performance capacity is mostly the chosen method.
Peak demand may only occur for a few hours and would differ from year to year. While heating systems consume energy for nearly half the year, and the system works at peak load for only week or so, then the rest of the year it is over-sized.
Using a diversity factor very much depends on judging the building on its 1) occupants 2) geographical location and climate 3) the building fabric.
For Heating design, refer to – BS EN 12831-1:2017.
Types of heating in apartments generally is either;
For dwellings over 150m2 Part L as good practice recommends two space heating circuits with independent time and temperature control, and thermostatic radiator valves.
The use of pre-settable radiator valves is recommended for the correct balancing of radiators.
DHWS demand is difficult to predict as it’s down to multiple factors involving peoples’ lifestyles, numbers of occupants per apartment, seasonal conditions, and work patterns. For this reason, a ‘factor’ is applied to attempt to replicate the situation where not everyone will be using hot water at the same time. In basic terms, the more apartments or homes the less likely it becomes that they are all running simultaneously, so we can reduce the peak design load. The design standards in Scandinavian countries have often been held as an example for this factor, such as the Danish Standard DS439. There is much debate as to whether this is suitably applicable to the UK, and other variations on this have been discussed but there is no printed standard.
The DS439 standard identifies 37.6 kW as the peak load for a standard apartment. The coincidence factor simulates how unlikely it is for all the individual apartments to be peaking at the same time, to prevent oversizing of the overall system. The diversity factor is the reciprocal of the coincidence factor.
For larger apartments or homes, then a common practice is to scale up the factor proportionately. In fact, this is not always true, because the larger apartment would not mimic the DHW requirements of two smaller households, though may have larger peak load. So, each project must be judged on its own requirements, and the coincidence and diversity factors are at best a guide.
Heat Interface Units (HIU) or Flat Station deliver heat generated from a centralised heating plant to multiple homes, apartments, or flats. The Inta Hiper Indirect HIU provides the interface (separation) between the heat network and the homes heating and hot water systems through plate heat exchangers. A control valve modulates the supply of heat to provide hot water (DHWS) and room heating (HTG) with stability and rapid response.
Heat from the main boiler plant is transferred to the home by two plate heat exchangers. One plate heat exchanger (PHE) provides the hot water supply (DHWS) and the other plate heat exchanger supplies the central heating circuit (CH). This can be by either radiators or underfloor heating; the installer has the option to commission for either. This is an Indirect HIU (heat interface unit).
The key strategy for Inta developing the latest upgrade of the Hiper II HIU was to have one HIU for the widest range of installations.
The solution is the combination of electronics, hydraulic control, and plate heat exchanger.
Extensive programme of HIU testing was completed under all possible network conditions to record how the Hiper HIU operates under these varied conditions.
Hiper II HIU uses Asymmetric plate heat exchangers designed specifically for heat interface units. Smaller channel volume in each plate, gives greater efficiency. But increase the pressure drop, and the system designer needs to size for bigger pumps and pipework. This in turn increase installation and running costs. The balance is between efficiency and pressure drop.
High Efficiency Asymmetric PHE Facilitate Low Primary Flow to achieve Low Return Temperatures
with reduced channel volumes. More plates, lower return temperatures and LESS PRESSURE DROP.
A Twin plate indirect HIU design is the most widely used HIU – it has 2 x Plate Heat Exchangers (PHE). The PHE separate the heating system and hot water system from the main plant. Twin plate HIUs are Hot water priority. This means all the power from the larger PHE is used to produce hot water and the heating if being called for is temporarily stopped. The DHW and HTG plate heat exchangers are sized to match the heat loads calculated for the size of the home they are to serve. The Hiper II HIU has PHE and electronic control so that one model will meet nearly all domestic requirements, large or small.
A Heat interface unit (HIU) unit with just one plate heat exchanger.
Single Plate HIU’s cover all the other applications.
V1 Heating Only HIU. One PHE to provide heating only.
V2 Heating Only as the V1, but with an additional Flow and Return connection on the outlet side for the Home (Flat or Apartment) so you can connect to a indirect type Hot Water Cylinder and have stored hot water. Just like a traditional boiler system.
V3 Direct HIU has one PHE, which produces instantaneous hot water just the same as a twin plate HIU. But the heating side has no PHE, so the water in the plant from the boiler is the same as is found in the radiators, and at the same pressure. These are being used more frequently now with the increase of low temperature heat networks.
V4 Hot water Only HIU. Produced in the same way as the twin plate and V3. Usually found in commercial building applications (shops, leisure centres, commercial kitchens etc) in one’ s or two’s, or where electric panel heating is used.
CIU Cooling Interface Unit. Used in city large multi-story blocks. Large areas of glass mean large thermal solar gains in summer, and chilled water plant is required to cool homes and offices.
For each apartment type, the peak demand flow rate has to be calculated. This is determined by the number of outlets (taps and showers). It is unlikely that all will open at the same time, but again a DHW peak load has to be estimated. First calculate the flow rate the apartment users will expect, and the calculate in kW the power needed to deliver the design flow rate and the temperature for the hot water. A key influence is the cold water in temperature, 10C is set as the base line, so to achieve 55C DHWS then the temperature ‘lift’ is 45C. In some HIU’s data sheets the temperature for HIU performance tables is 50C, so then ‘lift’ value is less, and the power rating for the HIU is greater.
DHWS demand is difficult to predict as it is down to multiple factors involving peoples’ lifestyles, numbers of occupants per apartment, seasonal conditions, and work patterns. For this reason, a ‘factor’ is applied to attempt to replicate the situation where not everyone will be using hot water at the same time. In basic terms, the more apartments or homes the less likely it becomes that they are all running simultaneously, so we can reduce the peak design load. The design standards in Scandinavian countries have often been held as an example for this factor, such as the Danish Standard DS439. There is much debate as to whether this is suitably applicable to the UK, and other variations on this have been discussed but there is no printed standard.
The DS439 standard identifies 37.6 kW as the peak load for a standard apartment. The coincidence factor simulates how unlikely it is for all the individual apartments to be peaking at the same time, to prevent oversizing of the overall system. The diversity factor is the reciprocal of the coincidence factor.
For larger apartments or homes, then a common practice is to scale up the factor proportionately. In fact, this is not always true, because the larger apartment would not mimic the DHW requirements of two smaller households, though may have larger peak load. So, each project must be judged on its own requirements, and the coincidence and diversity factors are at best a guide.
The likelihood of everybody opening all their taps and using their showers at the same time is extremely remote, in fact, it would never happen. So as mentioned before, system designs incorporate this into their pipework sizing. Over-sizing has obvious disadvantages in increased capital costs, as well as increased network heat loss. Terminology for building pipework is divided into Pipework Risers and Lateral Pipework. Risers are vertical, and lateral are horizontal. The effect over oversizing vertical pipes is less critical, and air and dirt can be easily eliminated, and low temperatures on the return riser pipework limits heat loss issues. In general, sizing with a ‘safety’ factor’ to allow for unknowns reduces thermal efficiency and increases costs.
Auto Fault Diagnostics are a feature in the Hiper II electronic controller. It can detect component failures and system operating anomalies. On initial power on, HIU self-diagnostics check is performed to identify any problems, and alert the installation engineer with a error or fault code being displayed on the controller screen. During the HIUs operational lifetime should a component fail then a Fault Code or Error Code will be displayed on the screen diagnosing the problem.
Optimised heating is a function which manages the lowest return temperatures by monitoring the rise in the temperature on the secondary return temperature sensor. As the room temperature starts to near the room thermostat set point, then the temperature in the return pipework will also start to rise. To optimise the efficiency of the heating function, the HIU controller will compensate this rise by modulating down the PICV to reduce the flow of heat into the heating PHE. This then stops the secondary return temperature continuing to rise. This is particularly effective with under floor heating, where temperature overshoot can be a problem. Less heat is wasted, and comfort levels improved.
A pump protection programme option will run the pump for a short period of time when heating is not required during warm weather periods, or if the apartment is empty. Pump manufactures warn that long non-operational periods may cause pump seizing or pump ‘sticking’ due to build-up of deposits from chemicals in the heating system.
Automatic closing of the control valve is standard when power lost to prevent scalding by uncontrolled high temperatures if the valve is unpowered in its open position. The controller retains enough power to close the control valve on loss of power supply. This also prevents unnecessary heat returns to the network.
For Frost protection go to parameter 23 on the Hiper II Controller.
Temperature sensor on the heating secondary return is used to identify potentially damaging low temperature and turns on the circulating pump to move system water to take advantage of available ambient heat to protect the HIU.
The PID controller has two modes of operation, DHW production which requires high power, and Heating which requires considerably much less power. When peak demand is made of the heat network in cold weather and all the users are switching on heating at the same time the HIU controller is configured to not allow 100% opening on start-up and so prevents the ‘over demand’ on the network. The heating demand for power is much less than for the hot water production, so as a factory setting this is set to 30% of the actual capability of the control valve. When a demand for hot water arises, then the control changes to DHW supply mode and allows the valve to open fully to satisfy demand.
The installation plan may require pipe work to be made up to the position where the HIU is to be installed, but at this stage not involve installing the HIU itself. At this ‘first fix’ stage not having the HIU in position eliminates risk of damage or even vandalism while the property is not secure.
Using the Jig allows pipe work to be installed without the HIU and saves the cost of the purchase of a ‘first fix rail’ for every HIU.
This simple and cost effective method allows the wall bracket, pipes, and isolation valves to be positioned. Then the Jig is removed, and the installer moves to the next installation and so on, until all first fix pipe work is in place, and allowing other trades on site to carry out their work. The HIUs can be installed simply on to the wall bracket and connect to the isolation valves at a planned later date.
On the pipe connections heat interface unit, isolation valves must be fitted with the exception of the safety valve discharge pipe. These must be of the type ‘flat face and loose union nut’ for secure watertight connection and seals on a Wras approved fibre gasket, and as listed in the accessories list.
Viewing access to Heat Meter calculator on the Hiper II HIU is on a ‘lift up’ hinged panel on the top of the HIU.. The heat meter calculator can be removed from the body and fixed face down to the panel inside the HIU casing. When meter reading is to be read, the panel can be opened from the outside of the HIU without removing the casing. It is more common that meter readings are done remotely by the Billing Company contracted to the building. Information will be gathered by data loggers and read by the billing company, who then bills the final customer, or homeowner or occupier. In some cases, the heat is required to be ‘pre-paid’ or ‘pay as you go’ (PAYG).
Heat Networks Best Practice – CP1 (2020) Heat Networks Code of Practice for the UK
CP1 (2020) outlines The challenges for heat network design.
Today we are supplying 3rd generation network temperatures, between 90 and 60C supply temperatures, carbon based heat source.
The UK, and the world has to move to lower carbon networks, 4th generation networks will require supply temperatures between 60 and 45C. Heat pumps are making their presence known.
For the future, we will arrive at 5th generation networks, ambient designs with supply temperatures at less than 45C. Hot water supplies will require boosting at point of use. Largely heat pumps and electric.
New changes in the 2020 document;
Pages 48, 51 and 56
CP1 (2020) Heat Networks Code of Practice for the UK advise that for radiator heating systems best practice is to commission correctly and for this designers must specify pressure independent TRV, (PTRV) with a room thermostat in the main living area.
The Inta PTRV thermostatic radiator valve with pre-setting is a radiator valve that performs the functions of a thermostatic valve and a differential pressure regulator. Each pre-settable thermostatic valve comes with six pre-set Kv values.
The valve comes complete with the EN215, class A efficiency rated Inta i-therm TRV valve head.
The flow rate pre-setting limits the maximum flow passing through the radiator and thereby ensures simple and effective radiator circuit balancing. The differential pressure regulator integral with the rad valve maintains a constant pressure differential so therefore maintaining the set flow rate.
Calcium Carbonate (CaCO3) is the main cause of scale problems. What we consider scale is known as the calcite form of calcium carbonate. Like many compounds’ calcium carbonate is a polymorph mineral, it can take different forms, but each form is made of the same parts. H20 itself is an example of a polymorph compound, it can take the form of ice, snow, water, steam……all H20 but in different forms.
Calcite scale forms when water is either heated or subjected to a change in pressure like when water flows out a tap or is being pumped. Currently, HIU manufactures are encouraged to keep the DHW plate heat exchanger hot to keep hot water response times as set in the BESA Test Regime.
The downside to this is scaling problems increase.
To counter this, Hiper II operators have the option to use the Heating PHE as the bypass, thus keeping the DHW PHE cooler while still having heat available at the entrance to the DHW PHE.
Scaling can cause premature equipment failure, reduce thermal efficiency and lead to premature maintenance, also see ActivFlo water conditioners.
Installation Instructions are available with the HIU or as a down load from the Inta website
Programming Guide is only available to authorised engineers.
Safety valve discharge pipe connection must meet all current building regulations and have a continuous fall. Safety valve discharge pipe must conform to BS6798.
Heat pumps are an important factor in the transition to low carbon technologies, and the Hiper II HIU has been tested and performance reports at temperatures down to 50C in the network supply have figures for consultants and engineers to work to.
