9
Safety thermostat cut-out
Error code 69
The HIUs configured to support low temperature heating
continuously monitor the safety thermostat controlling the flow
temperature.
If the safety thermostat is activated during a general cycle, the
heating circulation pump immediately comes to a stop and the
modulating valve is completely closed.
After the user has removed the block imposed by the safety
thermostat, operation can only be re-enabled when the modulating
valves are completely closed again.
This means that if a domestic water cycle is in progress, the
activation of the shut-off valve will be postponed until the end of that
domestic water cycle.
Removing a fault
To restore the operating mode press the manual
RESET button.
Safety and alarms
Error codes associated with faults signalled by illumination of the
FAULT LED are also shown on the display.
69
Removing a fault
Normal operating conditions are restored automatically once the
faulty probe is working properly again (see page 12 - “Temperature
probe replacement”).
Probe fault
If a temperature probe fails, the associated cycle will be stopped
immediately and disabled.
Any requests to run cycles not associated to the previous one will
continue to run normally.
Heating probe fault
Error code: 5
5
Domestic water probe fault
Error code: 6
6
Compensation probe fault
Error code: 15
Removing a fault
Restore the correct switch setting in accordance with the
procedure shown on pages 10-11.
Incorrect switch setting
Error code 79
79
Removing a fault
The heat interface unit is disabled due to incorrect setting of the
dip-switches. Restore the correct switch setting in accordance with
the procedure shown on pages 10-11.
Incorrect switch setting (heat interface unit disabled)
Error code 80
80
Heating circuit pressure switch fault
Error code 4
The electronic regulator continuously monitors the status of the
pressure switch controlling the water pressure in the heating circuit.
If the pressure switch is activated, the heating circulation pump
immediately comes to a stop and the modulating valve is completely
closed.
This fault implies the stoppage of the heating cycle only.
Domestic water drawing requests will continue to be served normally.
N.B.
: A low pre-charge value of the expansion vessel can cause a
pressure switch fault.
Removing a fault
Return to the operating mode is subordinate to restoration of the
correct water pressure in the secondary heating circuit (see page
6 - “Filling the user system”).
4
