20
ENGLISH
GENERAL
NOTES ON FUNCTIONING
The CH circuit (BAG) control card functions in conjunction with the main boiler control card to control:
- The anti-seize function that opens and closes the mixer
valve (if fitted) and the circuit pump for 10 seconds, at
intervals determined by the setting of the "ANTI-SEIZE
INTERVAL" parameter. This function serves to prevent
seizure of the pump rotor.
- The boiler frost protection function that protects the
heat exchanger if outdoor temperature falls below -5 °C
during total shutdowns.
- The CH circuit frost protection function that protects
the mixing column and the mixed CH circuits against
the risk of freezing. The mixed CH circuit temperature
sensors protect only the low temperature circuits; the
“BAG” card’s own sensor protects the high temperature
circuit. If the temperature detected by any one of the
sensors (mixed circuit or BAG) falls below 10°C, the
pump for the circuit concerned is switched on for a time
determined by the setting of the "FROST PROTECTION
TIME" parameter. If temperature rises above the 10°C
threshold during this time, the pump is switched off.
If temperature has not risen above 10°C by the end
of “FROST PROTECTION TIME”, but has not dropped
below the "FROST PROTECTION THRESHOLD", cir-
culation is re-activated for 4 minutes after 2 hours. If
on the other hand temperature falls below the "FROST
PROTECTION THRESHOLD" (irrespective of when or
how) a request for heat is generated and the boiler runs
at minimum power until the temperature detected by the
sensor (mixed circuit/BAG) rises above 10°C.
- The domestic hot water function, which prioritises
requests for domestic hot water and also prevents the
low temperature CH circuits’ maximum temperature
thermostats from tripping after a DHW request. When
domestic hot water is requested, this system stops the
low temperature circuit pumps and closes the mixer
valves according to the following logic:
- If temperature in the mixing column, detected by
the column’s own sensor, exceeds 3/4 of the system
setpoint, the CH circuit pump is allowed to continue
functioning;
- If temperature in the mixing column is below 1/2 of the
system setpoint, the CH circuit pump is stopped and
the mixer valve closed.
- The overtemperature dispersal function, which ensures
a uniform system temperature and disperses excess
heat towards the direct CH circuit that made the last
request for heat.
- The low temperature CH circuit protection function:
if an alarm is received from the maximum tempera-
ture sensor, this function stops the pump and clos-
es the mixer valve for the time set in the "FLOW
OVERTEMPERATURE STOP TIME" parameter. At the
end of this time, the pump remains in postcirculation for
the time set in the "SYSTEM RESET TIME" parameter. At
this point, if the over-temperature alarm has been reset,
the boiler returns to normal functioning; otherwise it
enters burner lockout.
- The chimney sweep function, which activates a full
power cycle for 15 minutes.
- The automatic temperature control function, which
permits the system to determine flow temperature from
the boiler to the mixing column, from the mixing column
to the low temperature zone, and from the boiler to the
high temperature zone on the basis of actual require-
ments. The "Central Heating Temperature Selector"
knob is NOT USED.
- The night-time temperature reduction function, which
automatically adjusts flow temperature and therefore
room temperature to suit the time of day or night.
- The floor curing function, which controls mixed CH cir-
cuits with a special logic to ensure optimal floor curing
(see the "Automatic temperature control" section).
