Baxi Luna 310 Fi Troubleshooting Guide - Baxi LUNA 310 Fi Troubleshooting Manual

BAXI LUNA 310 Fi troubleshooting guide

Fault Cause
Boiler does not start No power at the
no LED's lit. boiler
Boiler does not start #14 LED not lit
but #12 LED is lit. (call for heat)
Boiler does not start #13 LED not lit
but #12 LED is lit. (call for DHW)
Boiler does not start Low water pressure
but #12 and #13 or
#14 LED's are lit.
Primary/DHW sensor
faulty.
Pump not operating
Air in system
Flow switch faulty
Pump running, flow Air switch not
switch closed fan operating
not running
Suggested Solutions
▪
Check 120 Vac at power cord outlet.
▪
Check if main 3.15 amp boiler fuse has blown.
▪
No signal from external control. Remove wires from thermostat connections
1&2 at terminal strip and jumper it. If boiler starts replace switching relay.
▪
Open DHW tap fully, has pin moved out from DHW differential assembly to
close micro switch (green wires)? No; DHW flow valve diaphragm damaged
replace. If diaphragm OK clean and lubricate DHW valve rod. Yes; check
continuity across DHW micro switch, replace if faulty.
▪
Re-pressurize heating system till pressure gauge reads between 1-2 Bar
on gauge. Check for and repair leaks in heating system.
▪
Check DHW/ Primary temperature sensors for cold resistance of approx
11 K Ω (resistance reduces with increase in temp), replace if faulty.
▪
Check for 120 V at pump, if no power and sensors OK, replace main PCB.
▪
120 V at pump, but pump not turning. Release jammed pump by removing
vent cap on front of pump and turning shaft counter-clockwise. If pump will not
turn. Drain boiler, remove pump head release and clean pump cartridge.
▪
If pump is running but the flow switch has not closed, or is "bouncing" up
and down, purge air from the pump and heating system.
▪
If pump is running but flow switch has not closed; has pin moved out from
diverter valve to close micro switch? No; flow switch diaphragm damaged,
replace. If diaphragm Ok clean and lubricate flow switch rod. Yes; check
continuity across primary flow micro switch, replace if faulty.
▪
Check air switch has not stuck in the open position. To check, remove room
sealed door on boiler and pull suction tube from fan venturi. Gently suck on
the end of the sensing tube, you should hear the air switch operating. Re-
connect the sensing tube and retry lighting boiler, (signal from PCB to fan on
start is via the NC terminals on the air switch). If air switch OK replace PCB.
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