Boiler Maintenance
Cleaning and Maintenance
page 24
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B 034 00 04
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4
4.1.2
Maintenance schedule for safety devices
No.
Component / Maintenance Operation
Interval
1
System pressure
Read off the system pressure on the pressure gauge.
The value must be over the pre-stressed pressure of the
expansion tank by 20%
See the expansion tank operating instructions
If the system pressure is less:
Top up the water
If this occurs frequently it indicates that the heating system is
not sealed correctly. Call a service engineer.
If large pressure fluctuations are observed:
Have the expansion tank checked.
D
2
Back-fire flap
Check the seal and the efficiency of the back-fire flap.
W
3
Safety valve
(provided by the
customer)
Check the safety valve as per the manufacturer's
instructions.
See the expansion tank operating instructions.
M
4
Safety battery valve
Pull the safety valve sensor out of its immersion sleeve.
Hold the sensor in a heated water tank fitted with a temperature display.
Heat the water until the temperature reaches the setpoint value for the
valve.
At this temperature the valve must open and allow cold water to flow
into the safety battery.
After the test, push the valve sensor back into its immersion sleeve.
Check that water is flowing out of the safety battery drain pipe.
Clean or change the valve if it leaks.
Risk of scaling in the safety heat exchanger.
If the heat exchanger is badly scaled, the flow-through will be very small. In this case the
heat-exchanger must be descaled by a specialist company.
3-M
5
Safety temperature limiter (STB)
Pull the STB capillary sensor out of its immersion
sleeve.
Hold the sensor in a heated water tank fitted with a
temperature display.
Heat the water until the temperature reaches the
setpoint value (approx. 100
°C) for t
he STB.
The system will shutdown and a fault message will
be displayed.
If the system does not shutdown, the STB is
defective and must be changed immediately.
Resetting the STB by hand:
Allow the sensor to cool down and then screw the cap off the STB.
Reset the safety temperature limiter by pressing with a screw-driver.
6
Heating EMERGENCY STOP
switch
Test the efficiency of the emergency stop switch for
the heating.
Y
