6
Hot domestic water
The interface unit features a double wall heat exchanger which transfers the heat supplied by the district
heating network to the domestic water supply. Electronic control together with an electronic control valve
and a flow sensor in the interface unit ensure a domestic water temperature of approx. 55 ºC. The interface
unit has a low tapping threshold of 1 l/min.
Ex-works (default) the heat exchanger is continuously kept warm to supply domestic water as quickly
as possible in case of domestic water demand. Keeping warm takes place at a lowered temperature to
minimise energy consumption. By default the interface unit is provided with an anti-Legionella’s disease
function. To prevent Legionella’s disease the heat exchanger is heated once every 24 hours to at least 60 °C
for at least 90 minutes, whereby any Legionella bacteria are made harmless.
Note!
Hot domestic water
The domestic water temperature is controlled at approx. 55 ºC. With a power outage during hot water
tapping the interface unit stops controlling the domestic water temperature. This can result in domestic
water temperatures lower or higher than 55 ºC. Hot domestic water can cause burns.
Priority switching (optional)
The interface unit is available with optional priority switching. With hot water tapping a CH control valve
ensures that the full differential pressure from the district heating network is available for the heating of
domestic water. During hot water tapping the heat supply to the CH circuit is interrupted. After tapping the
heat supply to the CH circuit resumes again. With a power outage during hot water tapping or in a situation
where there is no heat demand from the (connected) room thermostat, the CH control valve remains in the
closed position. This can result in the cooling of the CH installation.
Installation conditions
With the installation of the interface units account must be taken of the current and applicable Buildings
Regulations, safety requirements for CH installations and general instructions for potable water
installations. The interface unit may only be installed by persons accredited in this discipline. Accreditations
are issued by the energy companies and electricity and water companies. The interface unit is only for
use in closed heating systems to a maximum temperature of 95 ºC. The plug must remain accessible after
installation and must be able to be simply removed from the plug socket.
The following conditions must be observed when installing the interface unit:
1. An associated pre-fix bracket of the same make must be used to ensure the proper operation of the
interface unit.
2. A water heater inlet combination (BIC) of 6 bar must be fitted on the cold domestic water inlet side of
the pre-fix bracket.
3. When using a room thermostat, it must be connected to the thermostat cable on the interface unit
if possible (electronic with priority). NOTE: refer to the technical table for permitted types of room
thermostats.
4. If the room thermostat cannot be connected to the heat interface unit but is connected to the district
heating valve, then the district heating valve must be fitted to the CH return pipe as close to the heat
interface unit as possible.
5. The interface unit must be installed in a frost-free space.
6. The interface unit must not be exposed to direct sunlight.
7. Ambient temperature range: +5 ºC to +40 ºC
8. Humidity range: 20% t/m 80%
