System water pressure adjustment
The filling pressure with system cold, read
on the boiler display, must be approx. 1.0
bar. If the system pressure falls below mini-
mum values, the boiler stops and fault F37 is
displayed. Pull out the filling knob (detail 1 -
fig. 26) and turn it counter-clockwise to re-
turn it to the initial value. Always close it af-
terwards.
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 di-
splay with system cold (detail 12 - fig. 1). In
case of a pressure below 0.8 bar, it is advi-
sable to restore it.
Display
F40
2.3
bar
1.2
bar
0.7
bar
F37
System draining
The drain cock ring nut is located under the
safety valve inside the boiler.
To drain the system, turn the ring nut (ref. 3
- fig. 27) counter-clockwise to open the
cock. Do not use any tools; use hands only.
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.
316
Description
High pressure
Pressure slightly high
Optimum pressure
Pressure slightly low
(The indication with the symbol
is visible only if parameter
b09 is set to 1).
Low pressure
cod. 3541V622 - Rev 00 - 05/2022
ALHENA TECH H
1
fig. 26- Filling knob
Operation
The boiler stops
The boiler works at reduced power
Normal operation
The boiler continues to work.
It is advisable to refill the system as soon as
possible.
The boiler stops
fig. 27
2
3
EN