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Diagram 3.1
CABLE
CLAMP/COVER
SCREW (2)
MAINS
CABLE
L
N
E
2
3
1
CABLE
CLAMP
2883
CABLE TO
REMOTE
HEATING
CONTROLS
3.1 Initial Checks
If the boiler fails to operate, first check the following:
1) That the electrical supply is available at the boiler and the fuses
are in order.
NOTE: THE BOILER CONTROL BOARDS CAN BE DAMAGED
BY INCORRECT TESTING WITH THE POWER ON.
2) Make sure that the system pressure gauge registers 0.7bar,
minimum, and that the automatic air vent works. Refer to Installation
Instructions, Section 11.2.
3) That the gas supply is available at the boiler and purged of air.
4) That the boiler is set for the required service.
5) With the boiler central heating selector switched “Off”, see
diagram 6.1 Installation Instructions, check that the domestic water
supply is available and water flows freely from the hot taps. Close
the taps.
6) With the boiler central heating selector switched “ON”, see
diagram 6.1 Installation Instructions, check that all heating system
controls, if fitted, are working correctly and calling for heat. If not
isolate the boiler from the electrical supply. Disconnect the rear
multipole connector at the base of the boiler and release the cable
from the clamp.
Remove the connector cover and dependent on the type of control
fitted test for continuity of mains at terminals 1 and 2, see diagram
3.1.
7) Check reset button - if red neon is lit press button. In certain
circumstances the red neon light may not come on, due to no
system demand. Turn on a domestic hot water draw off tap to
create a demand, the light should come on, if reset is required.
Allow the boiler and system to cool down waiting at least a minimum
of four minutes before pressing the reset button.
If this is satisfactory proceed with the detailed fault finding as
Section 3.3.
3.2 Clock/Timer
If the clock has failed it can be bypassed by isolating electrical
supply and gaining access to the control box. Refer to Section 4.14,
disconnect the clock wiring harness from the 4 way terminal block.
Fit a yellow link between the terminals Y1 and Y2.
This is a temporary measure and the clock should be repaired or
replaced as soon as possible.
3.3 Electrical
Preliminary electrical system checks, as outlined in a Multimeter
Instruction book, are the first checks to be carried out during a fault
finding procedure.
WARNING: Should fault finding have to be carried out on the CVI
box, see diagram 4.13. Precautions should be taken as this box
carries high voltage.
Isolate the boiler from the electrical supply, refer to Section 1.3.
Gain access to the boiler controls by removing the outer case, refer
to Section 1.4. Check that all cables and connectors are secure.
Gain access to the control board, refer to Section 4.14. Check all
cables at the multipin connectors on the board.
Test the two fuses on the main control board and renew as
necessary. Fuse 1 type (2AT), Fuse 2 type (3.15 AT). If a fuse fails
repeatedly or the initial fault-finding checks described in Section 3.1
indicate a boiler fault, check the boiler electrical circuits and follow
the fault finding procedures, see diagram 3.2, 3.3, 3.4, 3.5 and for
clock/timer fault finding, diagram 3.6 and 3.7.
On completion of a fault finding task that has required the
disconnection and making of electrical connections then checks,
for earth continuity, polarity and resistance to earth must be carried
out.
3 Fault Finding
