A.O. Smith DRE PLUS Installation, User And Service Manual page 34

EN
32
Safety devices of the water heater:
Main Safety thermostat
(G1)
Row Safety thermostat
(G2)
Thermal fuse
Safety devices of the installation:
Expansion vessel
Expansion valve
Pressure-reducing valve The pressure-reducing valve reduces the water
Temperature and pres-
sure relief valve (T&P
valve)
(1)
1- All installations have a T&P valve connection. The use of a T&P valve is mandatory.
The main safety thermostat (G1) breaks the con-
trol circuit when the water temperature is too high
(>92°C ±3°C). The main safety thermostat also
protects the heating elements when the water
heater is activated when it is not filled with water.
The main safety thermostat (G1) probe is installed
above the middle element of the highest row. You
can use the white button on the thermostat body
to manually reset the thermostat when the water
temperature has dropped (<83°C). Make sure the
water heater is completely filled with water before
resetting the thermostat.
The row safety thermostat (G2) breaks the cir-
cuit (L1 and L2) of each row of elements when the
temperature of the water becomes too high
(>93°C ±3°C) due to a failure in the control cir-
cuit. You can use the red button to manually reset
the thermostat when water temperature has drop-
ped (<83°C).
The thermal fuse is integrated in the wiring of the
main safety thermostat (G1) and breaks the con-
trol circuit when it detects overheat of the element
area. The thermal fuse cannot be reset. The com-
plete wiring, with thermal fuse, must be replaced.
The expansion vessel temporarily stores expansion
water to keep the pressure in the installation at the
correct level.
The expansion valve prevents excessive pressure in
the tank of the water heater.
mains pressure, if necessary.
The T&P valve prevents excessive pressure and
temperature in the tank.
Installation, Maintenance and Service part