ALHENA C
System water pressure adjustment
The filling pressure with system cold, read
on the boiler water gauge (detail 2 - fig. 15),
must be approx 1.0 bar. If the system pres-
sure falls below minimum values, the boiler
stops and fault F37 is displayed. Turn the fil-
ling knob (detail 1 - fig. 15) and turn it coun-
ter-clockwise to restore the pressure to the
initial value. Always close it afterwards.
Once the system pressure is restored, the
boiler will activate the 300-second air ven-
ting cycle, indicated on the display by Fh.
To prevent boiler shutdown, it is advisable to
periodically check the pressure on the gau-
ge with system cold. In case of pressure be-
low 0.8 bar, it is advisable to restore it.
System draining
To drain the system, attach a rubber hose
(ref. 3 - fig. 16) to the circulating pump drain
valve connection.
Using a hex wrench, open and empty the sy-
stem. To prevent the valve from becoming
detached from the circulating pump, do not
unscrew it completely.
To drain only the water in the boiler, first clo-
se the shut-off valves between the system
and boiler before turning the ring nut.
Information regarding the circulating pump
the circulating pump has a central button
(ref. 1 - fig. 17) for selecting the operating
head. If the circulating pump is controlled by
a modulating signal (as in this ALHENA C
model), the button is disabled and head
adjustment is automatically controlled by the
PCB.
There are some LEDs (ref. 2 - fig. 17) which
indicate the circulating pump operating mo-
de. Otherwise, in case of a fault, these LEDs
provide diagnostics of the possible cause,
based on the number of flashes.
cod. 3540000251 - Rev. 00 - 03/2024
1
fig. 15- Filling knob
3
fig. 16
2
fig. 17
EN
2
1
245