8
2.
For the Installer
2.2.4 Heating circuits
Several heating circuits:
In-line regulating valves should be installed to permit better regulation of the system. In a building without insu-
lation (new building, not yet plastered) the calculated and actually required heating requirements often differ to a
considerable extent.
Minimum heat consumption:
The smallest possible boiler power must be continuously dissipated from the boiler during operation. Suitable
measures to ensure minimum heat consumption should be maintained throughout the entire burning time, e.g.:
– Correctly dimensioned buffer tank - see 2.2.3.
– Function of the MES plus–controller in the WVF+ function module on the master user module
incl. no thermostatic valves
– Non-blockable heating circuit, e.g. never fully close manual mixing valve, incl. no thermostatic valves
Note!
If operating with a manual mixing valve or the MES plus–function, elevated room temperatures may
sporadically occur.
Mixer valve:
A 3-way mixer valve is always necessary; in conjunction with outside temperature control, there must be a 3-way
motorised mixing valve and a buffer tank.
Underfloor heating:
Only possible with a buffer tank (with outside temperature control, motorised mixing valve).
Return flow temperature increase:
Required with LogWIN Klassik. It is essential that
a return temperature of 61 °C be maintained during heating.
In order to achieve good temperature stratification in the heat accumulator or buffer tank, we recommend that
the boiler circuit be regulated. When using the return hold-up group SK RH 61 in connection with the stratified
charge function (MESplus function module WVF+), regulating the boiler circuit is no longer necessary.
Boiler start-up relief:
A boiler start-up relief must be installed and connected in all cases so that the circulation pump(s) are switched
off when the boiler temperature is below 60 °C. This prevents condensation forming in the boiler and extends its
service life.
A boiler start-up relief of this kind is contained in the MESplus control system.
2.2.5 Circulation pump
We recommend using pumps efficiency class A.
2.2.6 Heating water
a) The chemical composition of the heating water must meet the specifications of ÖNORM H 5195 Part 1 or VDI
2035 P1. According to ÖNORM H 5195 Part 1 (2010 edition), the condition of the heating water must be checked
every 2 years by a heating technician in order to avoid corrosion and sediment accumulation in the heating
system.
b) The pipe lines and heating appliances should be thoroughly rinsed before the boiler is connected.
c) To protect the boiler from contamination from the heating system, installation of a dirt trap is required in old
or existing systems (mesh size 0.5 mm) with maintenance cocks installed in the return line.
d) If oxygen diffusion or sludge build-up cannot be prevented, the system must be segregated by means of a heat
exchanger.
e) If antifreeze is used, a minimum volume of 20% antifreeze is required, otherwise corrosion prevention is not
guaranteed.
