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T e c h n i c a l N o t e b o o k . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
T e c h n i c a l T r a i n i n g
Regulation:
• Frost protection:
The frost protection function is activated when the temperature falls below 12°C at the start of the heating circuit.
The pump then runs for 10 minutes with the 3-way valve in the mixed position (central valve position to feed both the heating circuit
and the plate heat exchanger):
- If the temperature of the heating circuit falls below 7°C, the burner lights and remains alight until the temperature at the start of the
heating circuit reaches 35°C.
- If the temperature remains between 7 and 15°C, the burner lights after 30 minutes to raise the temperature to 35°C.
- If the temperature exceeds 15°C, the pump runs for 30 minutes and then stops.
• Protection against overheating and temperature limiting:
The outlet / return thermistors protect the boiler against overheating by checking the maximum outlet temperature (97 °C burner on or
110 °C for three seconds with the burners off).
Complimentary conditions related to the flow rate in the installation:
- check on the speed of temperature rise (10K/s max.)
- checking the temperature difference outlet – return:
- if ΔT (outlet-return) > 30K => the burner is forced to minimum power for 10 minutes
- if ΔT (outlet-return) > 35K => display of fault F23 initially volatile. If the fault repeats 5 times, the boiler shuts down and
a “reset” becomes necessary.
(Note: if the burner runs for at least 60 seconds, the counter is reset to zero)
T < 12°C
3-way in mixed position
+ pump ON for 10 mins
T = 7°C
Burner ON
T = 35°C
Pump 30 minutes
post-flush
7°C < T < 15°C
pump for
30 min
then burner on
up to 35°C
T > 15°C
Pump 30 minutes
pump OFF, 3-way
in initial position