Herz STOCKHOLM, Инструкция, Страница: 6 / 26

HERZ HIU STOCKHOLM
Page 6
Controlling the flow temperature of the domestic hot water
The temperature of the DHW is controlled by the tempering valve which is factory preset and will
require no adjustment.
Controlling the temperature of the heating system

The room heating temperature should be controlled by a programmable room thermostat and
thermostatic radiator valves which should be set to achieve the desired room temperatures.

To set the secondary flow temperature, please refer to controller literature for setting.
Testing

Check that the electrics are connected to a room temperature controller of some type and set it
to call for heat.

Check that the actuating drive opens the zone valve by watching the top and observing the
movement on the head.

Action the safety valve by twisting the head anti-
clockwise, don’t overdo this as you may need
to top up the secondary system.
Decommissioning, draining
If the HIU gets decommissioned for a longer period or dismantled because of certain reasons, the
decommissioning is carried out by closing all ball valves. In non-frost-protected rooms the
substation must get drained, before the cold season starts, if the substation does not get operated
for several days. When draining the substation, a vessel with a capacity of 4-8 litres should be
placed under the substation and the hot water, from the ball valves, should be tapped until the
substation is completely emptied. If there is a risk of frost, it should be noted that not only the water
in the transfer station and in the hot water pipes can freeze, but also in all cold water supply lines
up to the fittings and to the unit itself. It is therefore advisable to drain all water-conducting fittings
and pipes until to the frost-free part of the domestic water system.
Fitting the cover
When all the commissioning is completed fit the cover by locating the top of the cover over the lip
at the top of the back plate and lower down into position.
Operating requirements
In addition to the national regulations and standards, the connection requirements of the local
water supply organisations must also be observed
. The room in which the system is operating
should be free of frost and the location of the installation should leave enough space for
maintenance and repair works. The maximum flow temperature should be 100°C. In the primary
circuit the maximum allowable static pressure is 16 bar and the maximum differential pressure is 55
kPa. Furthermore it has to be checked that the connection pipes can resist temperatures with a
maximum of 120°C in case of damage.