31
Mexico Slimline RS 3/40 & 3/50 -
Installation
NO
NO
Is there a spark at the ignition electrode ?
47 PILOT WILL NOT LIGHT
48 PILOT WILL NOT STAY LIT WHEN THE GAS CONTROL VALVE KNOB IS RELEASED
Note.
After any faults have been corrected, return all thermostatic and other controls to the previously noted settings
NO
Check the boiler thermostat. Reference may be made
to the British Gas Multimeter Instruction Book.
Does the main burner light ?
Is there a supply voltage between the gas control valve
terminals ? Expect 230 V +10% -6%
YES
Set any CH and HW controls to the 'Continuous'
position. Is there a supply voltage between CH and N,
also between HW and N? Expect 230 V +10% -6%
Is there a supply voltage at the input to the control box?
FAULT FINDING
YES
NO
YES
Replace the gas control valve
Check that the gap between the electrode and the pilot
burner is 3-4 mm. Refer to Frame 37.
Check that the HT lead and electrode are undamaged
and the connections are NOT close to earthed metalwork.
Check the piezo unit is operative by holding an earthed
screwdriver approx. 3mm from the HT output terminal
(with the ignition lead removed) and by operating the
button.
Is there a spark across the gap ?
49 PILOT LIT BUT NO MAINS GAS
If no supply, check the controls. Reference may be
made to the British Gas Multimeter Instruction Book.
NO
Check the supply voltage, e.g., by using a multimeter,
set on the 300V AC range, between the L and N
terminals. Expect 230V +10% -6%. If no supply,
check the fuse in the plug or other supply point.
Have you confirmed that the system controls
are 'Calling for Heat' ?
YES
NO
YES
Check the settings of the room thermostat and the
cylinder thermostat. Check the control system.
Reference may be made to the British Gas Multimeter
Instruction Book.
Is there gas at the pilot burner when the gas valve
knob is pressed ?
YES
YES
Does the pilot light when a match is applied ?
NO
NO
Allow time to purge any air
present by increasing the pilot
gas rate (done by adjusting the
screw).
Check that the gas control knob
is being pressed fully in, that
there is gas pressure at the boiler
inlet and that the pilot jet is not
blocked.
NO
YES
Faulty
piezo
unit -
replace
NO
Check that there is no blockage in the pilot line or
pilot injector.
Adjust the pilot to correct size (flame enveloping
approx. 13mm of the thermocouple tip).
Confirm satisfactory ignition using the piezo unit.
Before attempting any electrical fault finding ALWAYS carry
out preliminary electrical system checks, i.e. earth continuity,
polarity and resistance to earth using a suitable meter.
Detailed instructions on the cleaning and adjustment
or replacement of faulty components are contained
in the 'Servicing' section of this publication.
Replace the
gas control
valve
Faulty piezo
unit - replace
F
AUL
T FINDING
Does the overheat thermostat (if fitted) require resetting ?
Does the pilot now stay alight ?
YES
NO
Replace the gas control valve
NO
Check the thermocouple output (6-10 mV closed circuit). Replace
thermocouple if output is outside the stated range. Reference may
be made to the British Gas Multimeter Instruction book
Does the pilot now stay alight ?
YES
YES
Is the pilot flame correctly set to maximum ?
NO
Is the connection between the thermocouple and
the gas control valve clean and tight ?
Clean the contacts and reconnect securely
NO
Replace the overheat thermostat
Содержание Mexico Slimline RS 3/40
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