Lennox ROOFTOP FLEXY FCA Series Installation Operating & Maintenance Manual page 31

GAS BURNERS GAS BURNERS GAS BURNERS GAS BURNERS GAS BURNERS
BURNER DISASSEMBLY FOR SERVICE
AND MAINTENANCE PURPOSES
Please refer to the enlarged diagrams at the end of the section
(figures 29 to 31) for further help.
- Stop the unit, switch off the main switch and disconnect
the gas supply.
- Disconnect the PCB
switches (figure 29).
- Remove the flared flange
nuts either on the solenoid
valves or on the supply
float rails. Do not tamper
with the joints.
- Remove the nozzle float
rail and the control box. Be
careful not to damage or
change the setting of the
ionisation sensors or
ignition electrodes.
- Remove the limiters (2)
and deflectors (3) (see
figures 30 to 32).
- Déconnecter et déposer
les ventilateurs d'extraction avec leur conduit d'évacua-
tion des fumées.
- Release the pressure tap pipes from the pressure
controllers.
- Loosen the screws on the fume box and remove the
assembly with the fans by slightly raising to release the
screws before pulling it towards you. Always make sure
not to damage the PCB.
- Using a clamp, remove the turbines from the tubes on
the fume box side.
- Use a 50 mm diameter nylon brush to sweep inside the
upper and lower tubes. Extract the dust with a vacum
cleaner.
REASSEMBLY
Use the supplied rod in the compartment to reassemble the
turbines. Place the pointed end of the rod inside the hole on
the turbine end. Once inside the tube, push until the turbine
contact the tube. Pull back the rod and withdraw 2 cm first
before giving it ¼ turn. If the rod unhooks during the procedure,
pull out the turbine with the hook and repeat all the
aforementioned steps.
Page 30 - IOM / ROOF-TOP FLEXY™ Series
TROUBLESHOOTING
The fan does not work.
- Check the electrical supply as well as the CLIMATIC™
which should show a heat demand.
- Make sure that B17/18 minigas pressure controller is
closed.
- Make sure that B45/46 klixon is neither damaged nor
too hot.
- Check whether the fan motor is powered and whether it
can turn freely.
- Check the supply and ensure it can rotate freely.
The fan starts without an ignition spark
- Check the operation of the air pressostat (B21/22)
- Check the ignition electrode position (see figures 25 &
26).
- Clean any oxide on the electrode.
- Check that the wire or electrode connections are not
earthed.
The fan starts with an ignition spark but without a flame
- Check the gas supply pressure.
Figure 29
- Bleed the gas line.
- Check the injection gas pressure. Adjust the pressure
on the solenoid regulator, if necessary.
- YV51/52 solenoid valve does not work : check the
supply voltage. Replace it if necessary.
The fan rotates, the flame is lit but goes out without
disconnecting
- Gas flow is too low, the pressure drops when the
solenoid valve opens.
The fan rotates, the flame is lit but goes out with disconnecting
(figure 20)
- Incorrect position of the ionisation sensors.
- Faulty connections of the ionisation electrode.