3 | Design Information
14
M0691622_en | Installation instructions TM 320-550
For the correct dimensions of the storage tank and the line insulation (in accordance with
ÖNORM M 7510 or guideline UZ37) please consult your installer or Fröling.
Additional requirements for Switzerland in accordance with LRV Appendix 3, section 523
Automatic boilers with a rated thermal output ≤ 500 kW must be equipped with a heat
accumulator of a volume of at least 25 litres per kW rated thermal output.
3.8 Return lift
If the hot water return temperature is below the minimum return temperature, some of the
hot water outfeed will be mixed in.
NOTICE
Risk of dropping below dew point/condensation formation if operated without return
temperature control.
Condensation water forms an aggressive condensate when combined with
combustion residue, leading to damage to the boiler.
Take the following precautions:
r
Regulations stipulate the use of a return temperature control.
Ä
The minimum return temperature is 60 °C. We recommend fitting some kind of
control device (e.g. thermometer).
