
U
SER
’
S
AND
I
NSTALLER
’
S
M
ANUAL
F
AULTS
Version: 4.0 (23-08-2007)
51
F3
For water-heated models:
The central heating system switches
on later than the unit.
You may:
• switch on the central heating system earlier;
• allow the unit to switch on the central heating sys-
tem (see section
4.5.6
, option 13);
• disable this fault message at the installer’s level (see
section
4.3.3
, function no. 72).
For water-heated models:
Underheating.
This fault may occur:
• if not enough hot water is sup-
plied;
• if the control valve does not
work correctly.
1.
Check the central heating system:
-
is it turned on?
-
is it able to supply enough hot water?
2.
Check if the entire heat exchange element gets hot: if
not, vent it.
3.
CA S/M: Check the LED on the valve drive: it must
come on when a higher or lower heating strength is
being set.
4.
Check the wiring and connectors of the valve drive
(X230) and the inlet air temperature sensor (X360).
5.
Take the drive from the valve, and check the interior
for mechanical operation and defects.
Electrically-heated models:
There is too little heating because
one or more heating elements do
not work.
1.
Check the mains fuses.
2.
Check the wiring and connections of the heating ele-
ments, using the wiring diagram as a reference.
If they are OK, a relay is defective: contact Biddle.
For all models:
The connections of the temperature
sensors have been interchanged.
1.
Check connectors X350 and X360:
connector X350 must be coded red.
F4
The temperature sensor in the con-
trol panel is defective.
The room temperature control is
now based only on the sensor at the
unit’s air inlet.
Replace the control panel if you want to make the room
temperature control work based on the sensor in the
control panel (see section
4.3.3
, function no. 51).
F5
The temperature sensor in the dis-
charge section does not work.
1.
Check the sensor’s wiring and connection (connector
X350).
2.
Replace the sensor.
F6
The temperature sensor in the inlet
section does not work.
1.
Check the sensor’s wiring and connection (connector
X360).
2.
Replace the sensor.
C
ODE
L
IKELY
CAUSE
W
HAT
TO
DO