Astra H-25 ES Manuale di installazione e sfruttamento - Pagina 4

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Description of the principal scheme of the boiler room. When the water temperature in the

boiler reaches 60

C there is launched circulation pump connected with the boiler. Water circulates through the

thermostatic mixing valve in the cycle „boiler – thermostatic mixing valve – boiler".

Heating system is equipped with the programmed automatic control processor and 3-way mixing

valve with electric drive (if the heating system is not equipped with the programmed automatic control processor

and 3-way mixing valve with electric drive there can be installed manual operation 3-way mixing valve and to

perform the regulation of heating system in manual way). When the water temperature rises further the

programmed processor control and regulate the temperature of the water supplied from the accumulation tank

to the heating system. This temperature

measured with the sensor.

In order to avoid the corrosion of boiler caused by the water condensate in the temperatures below

C thermostatic mixing valve automatically ensures that the minimal temperature of water returning to the

heating boiler is 60

Installing the boiler, the following requirements should be fulfilled:

The boiler should be installed in a closed heating system with a closed (membranous)

expansion vessel, the volume of which should be no less than 10% of the total volume of a

heating system (including the boiler). The closed heating system is the system with no free

access to atmospheric air, which actuates corrosion. Due to this, it is restricted to drain water

from the system without a particular reason (e.g. in summer, etc.). It is also necessary to ensure

tightness of the system in order to need fewer refills with fresh water having free oxygen.

Quantity of the additional water should not exceed 5% of water volume of the system per year.

Boiler should be connected (see the fig.2) to the heating system with the connection nozzles for

the supply of water to the heating system (pos. 10) and for the return of water from the heating

system (pos.11). Female threads of the nozzles pos. 10 and 11 are G 1

(Fig. 2) is designed for the inlet or outlet of water. The male thread of this nozzle pos.14 is G

Safety valve corresponding the requirements of standard EN 1268-1 should be installed in the

accessible place together with the corresponding temperature and pressure gauge.

Instrument

Safety valve

Temperature – pressure

gauge

There must be no shut-off valves between the boiler and safety valve.

Water from the safety valve should be conducted via an offtake duct. It should be conducted in the

way that the water let by the valve would safely flow, avoiding exposure with people and electrical parts of the

boiler. The diameter of the offtake duct should be no less than the diameter of the offtake opening connection

branch of the safety valve. Total length of the offtake duct should not exceed 2 metres. Installing this duct, no

more than 2 elbow joints at 90

installed in the valve water offtake duct. This duct should be installed in the way to see the offtake flow of the

water. If the end of the duct is to be hidden (e.g. in the sewerage pipe), then this duct should have a special

funnel enabling to see the offtake flow of the water.

WARNING! Operation of the safety valve should be checked at least once per month. The valve is

opened for a while by turning its head to see a small quantity of the offtake water. Avoiding this,

due to a high temperature impact, the components of the valve may stick together and serious

damages of the boiler and the heating system may occur as well as danger arise for human health

and life.

WARNING! In order to guarantee a natural water circulation in the boiler, the pipeline between the

boiler and the four-way mixing valve (boiler – four-way mixing valve – boiler) should be of the same

diameter and meet the diameter of the boiler connection branches.

The boiler will operate in the most effective and economic way, if a circulating pump is installed

in the system. It should be installed behind the mixing valve in the pipe of returned water. This

guarantees a constant water flow in the heating system. The pump is controlled with the

depends very much on the outside and ambient temperatures

Technical characteristics

Connection diameter does not

exceed ½", opening pressure

2 bar

Connection diameter does not

exceed 3/4", opening pressure

2,5 bar

Range of pressure 0-4 bar

Temperature 0-120°C

angles should be used. No closed, adjustable or other reinforcements should be

". The nozzle pos. 14

Type of boiler

Astra H-25 ES, Astra H-31,5 ES

Astra H-45 ES

All the boilers

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