0020244997_07 Installation and maintenance instructions
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5.7
Safety Devices
5.7.1
Electrical Supply Failure
The boiler will not work without an electrical supply. Normal
operation of the boiler should resume when the electrical
supply is restored.
Reset any external controls, to resume normal operation of
the central heating.
If the boiler does not resume normal operation press the
reset button. If the boiler does not resume normal operation
after this call your Installation/Servicing company or Vaillant
service.
5.7.2
Overheating Safety
The boiler software is designed to recognise the potential for
an overheat lockout and will shutdown before this happens.
To restart the boiler, press the reset button on the boiler
interface.
If the boiler fails to resume normal operation and all external
controls are calling for heat, then call your Installation/ Servi-
cing company or Vaillant service.
5.7.3
Frost protection
The appliance has a built in frost protection device that pro-
tects the boiler from freezing. With the gas and electric sup-
plies ON and irrespective of any room thermostat setting, the
frost protection device will operate the pump when the tem-
perature of the boiler water falls below 12 °C.
A timer is used so that the temperature can be checked peri-
odically. After 10 minutes the pump will be stopped if the
temperature is higher than 10 °C or has already reached
35 °C. The burner will activate if the boiler temperature does
not reach 10 °C after 30 minutes or at any time if the temper-
ature drops to 5 °C.
The burner will switch off when the temperature reaches
35 °C.
5.7.4
Condensate Drain Blockage
As a safety feature the boiler will stop working if the con-
densate drain becomes blocked. During freezing conditions
this may be due to the forming of ice in the condense drain
external to the house. Release an ice blockage by the use
of warm cloths on the pipe. After pressing reset the boiler
should restart.
