A.O. Smith SGE, Installation And Operation Manual

Page: 14 / 110

Working principle of the appliance
14 Instruction manual SGE
2
gis
Cut-away view of the appliance
2.3 The appliance's
heating cycle
The net water temperature (T
net
) in the appliance is used to regulate when both
the gas burner and the solar heating system are started and stopped. T
net
is the
curve shown in the figure. The controller uses two measured values to calculate
this temperature: T
1
(7) and T
2
(13). In addition, temperatures S
1
and S
2
are
used by the solar heating system controller. 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
net
falls below T
set
, the water heating via the solar
heating system is started, however, only if the temperature of the heating
fluid (S
1
) is a certain (adjustable) value higher than the temperature
measured at the appliance (sensor S
2
). As soon as (T
net
= T
set
= T
solar limit
),
heating via the solar heating system is stopped. There is one exception to
this rule, and that is when T
solar limit
is set to a higher value than T
set
.
Legend
Only applicable numbers are
mentioned.
1. cover
2. hot water outlet
3. electrical connector block
4. electronic 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
17. burner
18. fan
19. air supply hose
20. hot surface igniter
21. flame probe
22. chimney pipe
23. siphon
24. insulation layer
29. pallet
55. heat exchanger (e.g. solar
heating system)
56. temperature sensor S
2