Baxi LUNA 310 Fi Troubleshooting Manual page 3

BAXI LUNA 310 Fi troubleshooting guide
Fault Cause
Fan running, #8 (50°) Air switch not
fault code flashing. operating?
Moisture in air
switch suction tube.
Dirt in fan venturi.
Scale at venturi port
Severe local wind
conditions.
Incorrect vent length
or configuration.
Boiler does not light No spark at burner.
#6 (30°) fault code
flashing.
No gas pressure at
gas valve burner test
port.
Boiler lights then goes No ground to boiler.
out, #6 (30°) fault
code flashing. Flame lifting off burner
or 'ghosting'.
Week or no signal
from flame sensor.
Boiler will not Minimum gas pressure
modulate. to high.
Suggested Solutions
▪
This may be due to excess vent outside of building. Trim vent back to wall.
Insulate vent in unconditioned spaces.
▪
Remove fan transition bend and inspect for debris.
▪
Remove fan transition bend and inspect for scale and deposits. Clear venturi
port with #32 index drill. If this does not cure problem replace fan venturi.
Note: scaling is probably due to vent sloping toward the boiler, ensure that
vent is sloping toward the terminal.
▪
Check position of terminal, avoid terminating where other buildings and plantings
will affect boiler flue operation.
▪
Check for incorrect vent installation or excess vent length.
▪
If all of the above are OK replace air switch.
▪
Check for 120 V at the spark generator. If voltage at spark generator, replace
spark generator. No voltage at spark generator, replace main PCB.
▪
Check gas supply to boiler, is gas shut off valve open?
▪
Check gas valve main solenoids with power turned off. Approx 175 Ω cold
resistance on both main coils. If low or open, change gas valve.
▪
Check inlet screen for blockage on inlet side of the gas valve.
▪
Check for good ground at outlet and at boiler.
▪
Exhaust venting has come apart, check installation. If long horizontal run of vent
suggest using support spacers, available as an accessory.
▪
Exhaust vent does not extend to the end of the terminal, rectify fault.
▪
Air supply to boiler insufficient, check for blockage and correct vent installation.
▪
Air in gas line.
▪
Check for minimum 1 mA flame currant from flame sensing electrode. No; clean
or replace electrode. Yes; replace main PCB.
▪
Remove black wire from modulating coil while boiler operating, check low fire
gas setting. Reset if required.
▪
Remove modulating pin and inspect. Check that when end is pulled it springs
back into place. If broken replace (this is usually broken when inlet gas pressure
is low, to much adjustment has been made on pin to try to get boiler to high fire).
▪ Check voltage across modulating coil when operating, approx 10 Vdc high fire
1.5 Vdc low fire.
▪ Cold resistance on modulating coil approx 40Ω (with power off), if low or open
replace coil.
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