Herz STOCKHOLM, Инструкция, Страница: 2 / 26

HERZ HIU STOCKHOLM
Page 2
Function
In the stand-by mode the heating water flows from the primary circuit (district heating main) via a
summer bypass which is kept at operating temperature with a return temperature limiter. Thus
heating water from the primary circuit is always and immediately available at the heat exchanger,
even when the space heating is not in use. If a hot water tap is opened the pressure temperature
control valve reacts to the difference in pressure and opens allowing the cold and primary heating
water to flow through the heat exchanger. At the same time, a hot water priority valve closes the
primary feed to the secondary heat exchanger, thus ensuring maximum temperature is available at
the domestic heat exchanger. The cold water is heated up instantly and flows through to the
domestic hot water tap. The temperature of the domestic hot water is controlled by a thermostat.
Using an immersion sensor, this thermostat controls the temperature of the hot water that exits the
heat exchanger and regulates the pressure / temperature controller. A thermostatic tempering
valve is provided to ensure a stable hot water temperature and as a guard against scalding.
General
All union nuts must be tightened after installation and before filling to ensure no leaks have been
caused through transportation vibrations and heat expansion
Warnings

The unit must be installed and connected by professional plumbing and heating engineers
only.

Only use original HERZ spare parts when maintaining the HIU.

Check all connections for leakages prior to starting up the heating system.

The user must not make any technical changes to the HIU. Otherwise HERZ will not assume
liability for any resulting damage.

The unit must be filled with water containing the correct amount of inhibitor, failure to do so will
invalidate the warranty.

If the property is to be left unoccupied for a prolonged period, it is recommended that the HIU
domestic pipe work is isolated and drained.
Risk of electrical shock
The actuating drive and pump are connected to mains electricity and any contact with live parts can
result in serious injury or death. The following should be observed:

Please ensure that the power supply is isolated before removing the cover and when working
on any electrical components.

Only qualified electricians should carry out work on electrical systems.

Electrical components must not be touched with wet or damp parts of the body.

Electrical cables must not be pulled or any force exerted.

The Herz HIU must be connected to the electrical supply via a 3 amp fused switched spur so it
can be isolated from the mains.
Surfaces of individual components, connections and leaking water can be very hot and cause
severe burns and scalds. Before the start of any dismantling work the isolation valves must be
closed and water drained out. Out flowing water is likely to be hot and under high pressure. Take
appropriate precautions.
If a fault occurs, please contact the installer. Do not attempt to carry out repairs yourself.
System Balancing
Differential pressures higher than 55kPa could affect the performance of some components in the
HIU. Excessive differential pressures can also cause noise and reduce the lifetime of components
within the HIU. We would recommend the integral DPCV should be set to protect the components
in the HIU from excessive differential pressures.