Blue Seal 203926, Руководство по обслуживанию

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Revision 7/F3527
© Moffat Ltd, November 2004
Burner flame not being sensed
Firstly check phase and neutral at supply for
correct polarisation, as shown on terminal
block label. If incorrect burner will light but
flame sensor will not sense the flame.
The flame sensing electrode requires correct
positioning in the burner flame. Incorrect gas
pressures, types, injector sizes, etc will affect
correct operation of flame sensing system.
Ensure that these are checked and correct
before carrying out further investigation. Also,
an incorrectly earthed/grounded appliance will
cause faults with the flame sensing system.
Always ensure a correct earth/ground
connection on the appliance connection and
supply.
If the flame rod is touching the burner mesh
then there is a short circuit to earth, and this
will cause the ignition control to not sense the
flame correctly. As the relationship of the
flame rod to the burner mesh cannot normally
be seen, this fault would normally be indicated
by a burner that fails to stay alight during
operation, or during an ignition attempt the
sparking continues after the burner is lit. The
flame rod can be adjusted to be clear of the
burner, as per the previous diagram (figure
6.1.1) and section 11.3.
Always inspect the connection lead from the
flame rod to the ignition box for deterioration,
bad connections, or insulation breakdown.
Ignition transformer faulty - 110V models
only
It is important to verify correct 110Vac - 24Vac
transformer operation before checking these
24Vac Ignition Control Boxes.
With control panel open check transformer
primary and secondary voltages are correct.
Transformer Primary Winding - 110-120Vac
Lead colours
White - L1 (Phase)
Black - L2 (Neutral)
Check voltage at transformer terminal block
(pre serial number 203927) or at black an
white lead connections on control panel.
Voltage should be 110-120Vac. If not, check
for wiring or power supply fault.
Transformer Secondary Winding - 24Vac
Lead colours - yellow and blue
Check voltage at transformer terminal block
(pre serial number 203927) or at yellow and
blue lead connections on ignition control box.
With thermostat on (calling for heat) voltage
should be 24Vac ± 4Vac across yellow and
blue leads. If not, check transformer thermal
breaker on rear of transformer for trip. If
tripped, reset and recheck operation.
If the transformer cannot be reset, or if
transformer has not tripped out, but secondary
output voltage is incorrect, then transformer is
faulty - replace.
Ignition box faulty - 110V models only
The direct spark ignition control boxes used
on 110V models G32’s are 24Vac type.
To check correct operation open control
panel. With power on, turn thermostat on so
heating indicator on control panel illuminates
(calling for heat).
Correct ignition box operation should result in
ignition box commencing spark at ignition
electrodes and opening gas valve to ignite
burner, then maintain burner ON after
successful ignition.
If no spark is generated or heard, check that
ignition box has correct supply voltage. For
units pre-serial number 203927 fitted with
White Rodgers controls, check voltage across
terminals ‘COMM’ (black wire) and ‘TH’ (red
wire).
For units after serial number 203927 fitted
with Fenwal ignition controls check voltage
across terminal ‘GND’ (black/green wire) and
‘TH’ (blue wire).
On both types 24Vac ± 4Vac should be
measures across these terminals with
thermostat on and calling for heat. If not,
check transformer (refer previous).
If voltage correct, but no spark generated,
check ignition box Fault Diagnostic LED
indicator status.
On Fenwal ignition boxes, the Diagnostic LED
is at the rear of the ignition box and requires a
mirror or reflective surface to be positioned at
the rear of the control box to view.
On White Rodgers ignition boxes the
Diagnostic LED is at the top of the ignition box
inside the casing and is viewed through a
Figure 6.1.1
FLAME SENSOR
THIS ELECTRODE
MUST BE IN BLUE FLAME
SURFACE COMBUSTION
ORANGE INFRARED BURN
BLUE FLAME
SPARK ELECTRODES
THESE ELECTRODES MUST BE IN
SURFACE COMBUSTION ZONE
BURNER MESH
BURNER BODY
AS VIEWED FROM FRONT OF OVEN
BURNER VENTURI