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8.3.6 Frost protection
Install the boiler in a frost-free room. If the temperature
of the central heating water drops too low, the built-in
frost protection is activated.
Water temperature:
- below 7˚C
- circulation pump is switched on;
- below 3˚C
- boiler is switched on;
- higher than 10˚C
- boiler and circulation pump are
switched off.
Attention:
This is only a protection of the boiler.
It is recommended to install a frost thermostat (Tf) in
frost-sensitive rooms and connect it to terminals 13 and
14 of the 16-pole wire connector.
8.3.7 Signals
The boiler is supplied with remote alarm and boiler run
signalling facility. The alarm signal operates via termi-
nals 6 and 7 and whilst the boiler is operational a 24V
AC signal (power 4 VA) is available to energise a relay.
In case of failure of any electrical interlock or mains
failure the 24V supply will be switched off. The alarm,
which is de-activated whilst there is a power supply
from the relay during normal operation, is now activated
by the failure of this supply.
The boiler run light is operated via terminals 15 and 16
which can also provide a 24V (4VA power) supply to a
relay. The light is illuminated at the start of the pre-purge
(code 1) and goes out on closure of the gas valve (code
7 or 8).
Tf
When the frost thermostat cuts in, the circulation pump
will also be switched on.
The frost protection can be connected parallel to the
modulating room control.