A.O. Smith SGS - 80 Benutzerhandbuch

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Instruction manual SGS
13
gis
2
Working principle of 
the appliance
2.1
Introduction
Topics covered in this chapter:
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2.2
General working 
principle of the 
appliance
The figure shows a cut-away view of the appliance.
In this appliance, the cold water enters the bottom of the tank through the cold 
water inlet (14). 
Once the appliance and the storage reservoir are completely filled with water, 
they are both constantly under mains water pressure. When hot water is drawn 
from the appliance, it is immediately replenished with hot water from the storage 
tank, which in turn is replenished with cold water.  The water in the storage tank 
is heated by a heat exchanger which is connected to the solar heating system.
The appliance is equipped with a gas/air premix burner (17). The air is drawn in 
through the fan (18). The gas is supplied via the gas control (16) on the intake 
side of the fan. The gas/air mixture is then blown into the burner. The modulated 
supply of gas and air ensures that the optimum gas/air mixture is always 
achieved.
A gas-fired heat exchanger (11) in the appliance heats the tap water further if 
necessary. The air required by the latter for combustion is forced into the burner 
(17) by the fan (18). 
The heated tap water leaves the tank through the hot water outlet (2). Once the 
appliance is completely filled with water, it will constantly be under mains water 
pressure. When hot water is drawn from the appliance, it is immediately 
replenished with cold water.
The gas is fed to the burner via the gas control (16). The modulated supply of 
gas and air ensures that the optimum gas/air mixture is always achieved. The 
special construction of the burner causes the mixture to form a vortex (cyclone 
effect) before it becomes ignited. This vorticity improves the ignition on the hot 
surface igniter (20), as well as ensuring optimum combustion efficiency. The 
special design of the heat exchanger (11) ensures that the flue gases are first 
led downwards via the combustion chamber, then upwards via the heat 
exchanger, and downwards again alongside the water in the tank. The flue 
gases gradually become cooler in the process. Because the cooled flue gases 
flow alongside the cold water lower down in the tank, they start to condense. 
This condensation causes latent heat energy to be transferred to the cooler 
water, thereby increasing the performance of the unit. The condensate yielded 
by this process is discharged via the siphon (23).
Heat losses are prevented by the insulating layer (24) in both the storage tank 
and the appliance itself. Both are enamel-coated on the inside to protect against 
corrosion. The anodes (9) provide extra protection against corrosion. Both are 
fitted with an inspection and cleaning opening (12) for maintenance purposes.