The iHIU uses a revolutionary new heat exchanger layout with plate heat exchangers in series, allowing the whole system to be accurately controlled using a single control valve for both hot water and heating.
- 40kw Domestic Hot Water, max 10 bar, 10-60c, with 65c Primary.
- 15kw Indirect Central Heating with fitted controls as follows:
- speed controlled central heating pump
- 8 litre expansion vessel
- 3 bar pressure relief valve
- pressure gauge (visual indication of low pressure must be provided to occupants)
- mains filling loop
- automatic air vent, accessible to occupants
- fixed orifice bypass on primary, outside heat metered circuit, that closes as load on system increases. (Options for thermal or fixed flow bypasses)
- Control of system to be performed by a single valve, as follows:
- full bore
- fast acting, < 6 seconds for full open to close
- visual indicator of valve position
- 100% shut-off against 10 bar differential pressure
- anti-tamper
- automatic close on power failure
- control system to provide the following:
- hot water temperature control
- sterilisation program
- central heating time and temperature control
- weather compensation option
- primary return temperature limitation
- closure of primary valve on drop in DHW flow
- variable hot water priority, reducing or stopping central heating load as needed to satisfy hot water demand
- differential pressure limitation
- primary flow limitation
- measurement and logging of primary flow rate and temperature, independent of heat meter, for confirmation of heat meter readings
- fault alarms (timestamped and stored to memory) to include:
- loss of mains power
- casing opened
- high-low central heating pressure
- high-low primary pressure
- failure of central heating pump
- failure of control valve
- overheat
- inaccuracy in heat meter reading (flow or temp)
- option during installation to connect to local WiFi, or to generate WiFi hot spot for network control
- network control to allow for both engineer and user interaction
- if using network control, users should be able to programme:
- hot water temperatures
- central heating times and temperatures
- system switch off
- all these settings should be time programmable, daily, weekly, monthly, and prolonged absence (holidays)
- if using network control, engineers should be able to:
- view system logs, including faults
- edit any system settings pertinent to function of system
- perform software updates
- if connected to a network with internet access, system will provide following functions:
- log data to remote server
- remote software update
- fault alarms, emailed where appropriate, to type of fault
- primary limitations on flow and kW to adjust and match to available output from plant
- Option for battery backup to allow hot water function to continue in a mains power failure
- Option for fitted heat meter, with further option to have front of meter user accessible through casing cutout
- Unit dimensions to be no more than 550mm wide, 350mm deep, and 550mm high
- All components front serviceable
- Casing fitted with security bolt
- Wiring centre to be DIN rail based, with independent security cover
- valve cable to be protected
- Options for isolation valves
- All feeds into property to top of unit, primary flow & return, and cold mains in
- All services to bottom of unit, cold & hot mains, and primary flow & return