Phenomenon
Possible Cause
How to check
Result
Remedy
VAL6 MPX5/MPX1 Troubleshooting
Misfire lamp is lit.
Loose flame monitor
Open burner cover, and check if the
flame monitor is in
If flame monitor comes off, it
doesn't work
Put in flame monitor firmly
Shortage of light sensed from
flame
Take flame monitor out, and then
check clarity of its lens
If lens of flame monitor is dirty less
sensitive.
Wipe lens of flame monitor with
soft cloth
Remove burner, and then check clarity
of burner cone and vane
If burner cone or fan is dirty, it
senses little light
Clean burner cone and whirl vane
Check extent of combustion air inlet
opening
If opening is too extensive, flame is
short because combustion air is too
much
Decrease opening to reduce
combustion air.
Normal scale:
MPX5 - 2.5
MPX1 - 4.5
Loose connection of flame
monitor
Plug flame monitor connector (CN
11) again, and then turn on
If it works normally, flame monitor
connector fails on contact
Plug connector (CN 11) firmly
Failure of flame monitor
Measure voltage at flame monitor
connector on burner controller
standard
dark - about DC5V
light - DC1.2V and under
If voltage doesn't change, flame
monitor fails
Replace flame monitor
Nozzle clogged
Replace nozzle
If it ignited, nozzle is clogged
Replace nozzle
Filter element clogged
Check clarity of filter element
If filter is dirty, fuel flow decreases
because of filter element clogged
Clean or replace the filter element
3
．
Misfire within 10
seconds after ignition.
9
