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28
7.7.4
REVERSED POLARITY OR SUPPLY FAULT
Repeat the above tests at the appliance isolator,
if testing reveals correct polarity and/or supply at
the isolator, re-check wiring and connections
between the isolator and the appliance.
If tests on the isolator also reveal reversed polar-
ity or a supply fault, consult the local electricity
supplier for advice.
7.7.5
RESISTANCE TO EARTH CHECK
Isolate the appliance from the electrical supply
and using a suitable multi-meter carry out a
resistance test. Connect test leads between the
Live & Earth connections at the appliance termi-
nal strip (fig.16). If the meter reads other than
infinity there is a fault that must be isolated, carry
out a detailed continuity check to identify the
location of the fault.
IMPORTANT
These series of checks must be carried out
before attempting any faultfinding procedures on
the appliance. On completion of any task that
required the disconnection and re-connection of
any electrical wiring or component, these checks
must be repeated.
7.8
FAULT FINDING
Before attempting any faultfinding, the electrical
checks as detailed in 7.7 must be carried out.
Isolate the appliance from the electrical supply.
Disconnect any external controls such as room
thermostats etc. from the boiler.
7.8.1
REPLACING THE MAIN PCB
When replacing the main PCB it’s essential that
the potentiometers are set as follows:
●
It’s essential that the minimum - central heating
- gas pressure is checked/adjusted as de-
scribed in 7.3.3
●
P4
- to be used to set/adjust the minimum
heating output
●
P5
- set at maximum.
EFFECT OF JUMPER TAGS FITTED TO THE
MAIN PCB AT:
●
JP1
- disables DHW function
●
JP2
- cancels anti-cycle function and initial
heating output (75% of maximum at start up)
●
JP3
- for LPG boilers only
●
JP4
- enables DHW temperature stabiliser
function (boiler modulates at set point and
remains on minimum power, even if the set
point is exceeded).
NOTE
If the Vokera remote-control (RC05) is connected
to the appliance, it should be disconnected during
any faultfinding checks.
Restore the electrical supply to the boiler and turn
the selector switch to the on position. The boiler
should now function as described in section 7.2.
Should the boiler fail to respond, the internal
fuses and connectors should be checked to
ensure integrity and continuity. If the boiler still
fails to respond, refer to the detailed faultfinding
flowcharts overleaf.
Frequency
Faults/Status
ON every 0.5-secs
CO function active
Solid
DHW* thermistor fault (see 7.2.5.2)
YELLOW LED
* When there is a fault condition with the DHW thermistor, the
appliance will still operate and produce limited hot water. The
Primary thermistor will control the temperature of the DHW
during this period and the outlet temperature is fixed at 50-
55
o
C.
Frequency
Faults/Status
ON every 0.5-secs
Final fault, e.g.:
●
●
●
●
●
water pressure switch
●
●
●
●
●
condense pressure switch
●
●
●
●
●
fan/flue problem
●
●
●
●
●
limit thermostat
Solid
●
●
●
●
●
primary NTC open/short circuit
RED LED
7.9
FAULT CODES
When the boiler is in a fault condition, the LED is
displayed in a colour and/or frequency that is relevant
to the fault. To reset the boiler, turn the mode selector
switch to the reset position (0) for 2-minutes’ then back
to the relevant mode of operation.
If the boiler does not reset, refer to the following
section and the detailed faultfinding flowcharts
overleaf.
