Ariston ABS VLS EVO QH 100 D - Инструкция по эксплуатации - Страница 18

Anti-legionella recommendations (European standard CEN/TR 

16355) 

Informative 

Legionella are small rod shaped bacteria which are a natural constituent of all fresh waters. 

Legionaries’  disease  is  a  serious  pneumonia  infection  caused  by  inhaling  the  bacteria  Legionella  pneu-

mophilia or other Legionella species. This bacterium is frequently found in domestic, hotel and other water 

systems and in water used for air conditioning or air cooling system. Hence the main intervention against 

the condition is prevention, through control of the organism in water systems. 

The European standard CEN/TR 16355 gives recommendations for good practice concerning the preven-

tion of Legio-nella growth in drinking water installations but existing national regulations remain in force. 

General recommendations 

“Conditions for Legionella growth”. The following conditions encourage Legionella growth: 

•

water

 temperature between 25 °C and 50 °C. To restrict the growth of Legionella bacteria, the water tem-

perature shall be in a range that the bacteria will not grow or have minimum growth, wherever possible. 

Otherwise, it is necessary to disinfect a drinking water installation by means of a thermal treatment; 

•

stagnation

 of the water. To avoid long periods of stagnation, the water in every part of the drinking water 

•

nutrients,

 and sediment within the installation including water heaters, etc. Sediment can sup-

port the growth of Legionella bacteria and it should be removed on a regular basis from e.g. storage 

Regarding to this storage water heater, if 

1)

 the product is switched-off for a period of time [months] or 

2)

 the water temperature is kept constant in the range 25 - 50°C and the Legionella bacteria could grow in 

the tank. In such circumstances, reduce the proliferation of the bacteria by running a “thermal sanitisation 

cycle”. Water  heaters  are  sold  with  software  that  allows  a “thermal  sanitisation  cycle”  to  be  run  when  it  is 

activated  in  order  to  reduce  the  proliferation  of  Legionella  in  the  tank. This  cycle  is  suitable  for  domestic 

hot water systems and complies with the guidelines for the prevention of Legionella stipulated in Table 2 of 

standard CEN/TR 16355 (see below). 

Table 2 - Types of hot water system  

Separate hot and cold water

Mixed hot and cold water

No storage

Storage

No storage upline 

of the mixer 

valves

Storage upline 

of the mixer

valves

No storage upline 

of the mixer 

valves

No 

circulation 

of hot water

Circulation 

of hot water

No

circulation

of mixed 

water

Circulation 

of mixed 

water

No 

circulation

of mixed 

water

Circulation 

of mixed 

water

No

circulation 

of mixed 

water

Circulation

of mixed 

water

No 

circulation

of mixed 

water

Circulation

of mixed 

water

Ref. in

Annex C

C.1

C.2

C.3

C.4

C.5

C.6

C.7

C.8

C.9

C.10

Temperature

-

≥

 50 

°

C 

e

in

storage 

heater

a

≥

 50 

°

C 

e

thermal

disinfection

d

thermal

disinfection

d

in

storage 

heater

a

≥

 50 

°

C 

e

thermal

disinfection

d

thermal

disinfection

d

thermal

disinfection

d

Stagnation

-

≤

 3 l 

b

-

≤

 3 l 

b

-

≤

 3 l 

b

-

≤

 3 l 

b

-

≤

 3 l 

b

Sediment

-

-

remove

c

remove

c

-

-

remove

c

remove

c

-

-

a  Temperature ≥ 55°C all day or at least 1h a day ≥60°C.

b  Volume of water contained in the pipes between the circulation system and the most distant tap.

c  Remove the sediment from the storage heater as required by local conditions, but no less frequently than once a year.

d  Thermal disinfection for 20 minutes at 60°C, for 10 minutes at 65°C or 5 minutes at 70 °C at all delivery points at least once a week.

e  The water temperature in the circulation circuit may not fall below 50°C.

-  Not required

Electromechanical water heaters are sold with the thermal sanitisation cycle disabled (default setting). If, for 

some reason, any of the above “conditions in favour of the proliferation of Legionella” occurs, it is strongly 

recommended to enable this function according to the instructions found in this manual [see <<

Activating 

the “thermal disinfection cycle” (anti-legionella)

>>]. 

However, the thermal disinfection cycle does not kill all Legionella bacteria in the storage tank. It follows that 

if the function is disabled, the Legionella bacteria may reoccur. 

Note:

 when the software performs the thermal sanitisation treatment, it is likely that the power consumption 

of the water heaters increases. 

RU

EN

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