Technical data

50
This Fault Finding Chart is to be used in conjunction with the Operational Flow
Diagrams in Section 16. To find the fault, locate the point on the flow diagram at
which the appliance has failed, e.g. letter B. Then read the corresponding section
in the fault finding chart, e.g. Failure at point B. Note: Each section assumes
that the appliance operates correctly up to that point.
Note: 1. All voltage measurements are with respect to neutral unless otherwise stated. 2. Before changing any component indicated in the chart, it is essential that
the associated wiring is checked for continuity, condition and correct routing. 3. Preliminary electrical system checks are the first electrical checks to be carried out
during a fault finding procedure. On completion of the Service/Fault Finding task which has required the breaking and remaking of electrical connections, check –
(a) EARTH CONTINUITY, (b) SHORT CIRCUIT CHECK, (c) POLARITY and (d) RESISTANCE TO EARTH.
17. Fault Finding
Fuse has blown. Check condition of cables and all
internal and external electrical components. Repair
fault and replace fuse.
Heatbank Overheat Stat has
tripped. Investigate
reason/reset stat.
Check the mains electrical supply and
external wiring.
Is there 230V at X11
pin 4? (L)
Switch on the mains
electrical supply. Is the
Standby Indicator
illuminated?
Refer to Section:
FAILURE AT POINT A
or
FAILURE AT POINT J
STANDBY INDICATOR
DOES NOT ILLUMINATE
Is there 230V at the
top end of the fuse?
Is there 230V at pin 1 of
terminal X14?
(Left red wire).
Replace the Standby
Indicator.
NO
YES
YES
YES
YES
NO
NO
NO
START OF DOMESTIC HOT WATER TEST
Is there 230V at
pin 3 of terminal
X12?
(D.H.W.).
Is there 230V at
pin 2 of terminal
X12?
(L).
Is there 230V at
pin 1 of
terminal X2?
(Left pink wire).
Replace the operating switch
(or programmer)
Replace the hot water
control thermostat.
Replace the
control board
Replace the
control board
Replace the
control board
Replace the
pump
Set the operating
switch (or
programmer) to
WATER and turn the
hot water control stat
to maximum, but
keep the heating
control stat to off.
Does the pump run?
Is there 230V at
pin 3 of
terminal X2?
(Right pink wire).
Is there 230V at
pin 1 of terminal
X10?
(Brown wire).
NO NO
NO NO
NO
YES
POINT
B
YES
YES
YES
YES
YES
FAILURE AT POINT A