THERMAL INTEGRATION DATA Extra HIU, Installation Instructions Manual

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The DATA Extra HIU, Installation Instructions DE2, 12th August 2021
Operation
The HIU is equipped with two heat exchangers, the left hand heat exchanger transfers the heat from the district heating system to the
DHW circuit and the right hand heat exchanger transfers the heat from the district heating system to the CH circuit. These heat
exchangers ensure hydraulic separation between the property and the district heating network. The hot water in the district heating
network does not come into contact with the hot water or heating circuit of the property. Heat is transferred from the district heating
network via the heat exchangers to the domestic hot water system and central heating system.
Central heating
The temperature of the property's heating system is controlled automatically by the HIU, with the temperature set-point being
adjustable via the Modbus interface. When heating demand finishes, the heating pump will be switched off after a defined pump over-
run time (default: 15 minutes).
Domestic Hot Water
The electronics within the unit, together with domestic hot water control valve, temperature sensors and flow sensor, regulate the
temperature of the hot water to it's set point (As Standard 55°C). The HIU has a very low switching point, recognising DHW flow rates as
low as 1 l/min.
Each HIU has two domestic hot water keep hot modes, 'Eco' or 'Comfort' mode. These can only be selected during commissioning or by a
trained engineer.
'Eco' mode can be specified to run for 0 minutes (which turns the feature off all together), 15, 30, 60 or 120 minutes after the last hot
water draw off. In 'Eco' mode the heat exchanger is kept to a specified temperature (between 25 and 60°C) for the selected period of
time and after this period of inactivity has elapsed the control valve closes completely and the temperature in the domestic hot water
circuit is allowed to drop through natural dissipation to minimize energy consumption. If a hot water draw off is made any time
throughout the Eco mode function the unit will deliver hot water as usual and the 'Eco' mode function will begin counting down for the
selected time once again.In 'Comfort' mode the heat exchanger is continuously supplied with a trickle of primary water for quicker hot
water delivery, however energy consumption will be slightly higher than if the unit was set in 'Eco' mode.
To prevent legionella from growing the heat exchanger is heated to 60°C for at least 60 minutes every 24 hours. (it is not possible to
specify the time at which this occurs)
The hot water temperature is regulated to temperatures as high as 60°C. If there is a power outage during DHW draw off, units
not fitted with a landlord security valve will stop regulating the hot water temperature. This may lead to a hot water temperature
that is higher or lower than the setpoint. Hot water can cause burns.
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