Technical data

39
Alpha 240XP and 240XE - Fault Finding
10.3 DOMESTIC HOT WATER - Follow operational sequence
Turn thermostat to max.
Open DHW tap fully.
DHW flow valve operated
DHW flow rate more
than 2.5 L/min.
YES
DHW flow valve
diaphragm damaged
DHW flow valve
rod obstructed
Replace diaphragm
Is mains water filter and
differential assy. clean
NO
NO
YES
YES
YES
YES
Turn selector to and
go to section ' ', page 41
A
Primary water is diverted from
CH system to DHW heat
exchanger and flow
microswitch operated
Pump runs
Primary flow switch operated
Replace DHW flow
microswitch
Continuity across DHW
flow microswitch
and between
PCB terminals 35, 36
NO
NO
NO
NO
(240XE only)
YES
YES
Go to section ' ', page 41
B
Go to section ' ', page 41
C
YES
Fan runs at max. speed
NO
YES
Go to section ' ', page 41
D
Go to section ' ', page 42
J
Air pressure switch proved
NO
Go to section ' ', page 41
E
Burner output modulates
to maintain temperature
set at thermostat
NO
NO
YES
Clean DHW temp.
sensor and DHW
heat exchanger
Reduce DHW flow rate
from 10 to 5 L/min.
Burner modulates
NO
Close DHW tap
YES
DHW flow valve senses no
flow. Primary water diverted
to CH system.
DHW flow switch released (off)
Diverter valve spindle
assy. faulty
NO
YES
Burner goes out
YES (240XE only)
YES (240XP only)
Fan stops
Fan reduces to slow speed
YES
Operation sequence successful
Pump stops
YES
Go to section ' ', page 42
G
Spark at ignition electrodes
for upto 10 seconds
YES
NO
YES (240XP)
YES
Press red button to reset
NO
YES
Burner lights
YES
Go to section ' ', page 41
F
Go to section ' ', page 42
I
Go to section ' ', page 42
H
Red reset button
illuminated
But, burner does not stay
alight after 10 seconds
If still illuminated,
Go to section ' ', page 42
K
(240XE only)
YES (240XE)