Working principle of the water heater
14 Instruction manual SGE
2
gis
Cut-away view of the water heater
2.3 Water heater
operating cycle
The water temperature (T
1
) at the top of the water heater is used to control
when the gas burner is started and stopped. The temperature changes in the
water heater are used for switching the solar heating system on and off (using
T
1
and S
2
). T
1
is the curve shown in the figure. In addition, temperatures S
1
and
S
2
are used by the solar heating system controller. Temperature S
1
is
measured in the solar collector and S
2
between the inlet and outlet of the heat
exchanger (55).
The other settings that govern the control behaviour are:
•T
set
T
set
is the the required water temperature that has been set on the
appliance (11.4.1 "
Setting the water temperature via the SET POINT
MENU"). As soon as T
1
falls below T
set
, the solar heating system starts
heating the water, but only if the temperature of the heating fluid (S
1
) is
greater than the temperature measured at the appliance (sensor S
2
) by a
given (adjustable) amount. When T
1
= T
set
= T
solar limit
, heating by the solar
heating system stops. There is one exception to this rule, which is when
T
solar limit
is set to a higher value than T
set
.
Legend
Unused numbers are not applicable
1. cover
2. hot water outlet
3. electrical connector block
4. controller
5. pressure switch
6. control panel
7. temperature sensor T
1
8. combustion chamber
9. anode
10. tank
11. heat exchanger
12. inspection and cleaning
opening
13. temperature sensor T
2
14. cold water inlet
15. drain valve
16. gas control valve
17. burner
18. fan
19. air supply hose
20. hot surface igniter
21. flame probe
22. chimney pipe
23. condens trap
24. insulation layer
29. base
55. heat exchanger (e.g. solar
heating system)
56. temperature sensor S
2
58. flue gas test nipple
59. pressure-reducing valve
