Lochinvar EcoSword LGC 160-210 G P CE Installation, Commissioning, User & Maintenance Instructions page 74

Code and description
F03 (lock out error)
Air proving switch error
Switch is not closed when
fan is running during pre-
purge.
74
Cause
Hoses are damaged.
Wiring is damaged.
Leakage of air between venturi and
flexible air connector.
Non return valve, between fan and
burner, is stuck.
Not enough pressure differential across
the air proving switch, due to:
- venting system
- malfunctioning condensation
discharge
- dirty burner
- blocked heat exchanger
Measure
- Make sure that the hoses, between
the air proving switch and fan and the
air proving switch and gas control
valve are not damaged and reset the
controller.
- If necessary replace the hose(s)
- When the hose(s) are replaced and
reconnected, reset the controller.
- Make sure that the wiring, between
the air proving switch and the control,
is connected and not damaged.
- If necessary, replace the wires or
reconnect the wires.
- When wires are replaced or
reconnected, reset the controller.
- Make sure that the flexible air
connector is not damaged. If
necessary, replace the flexible air
connector.
- Make sure that the hose is properly
connected to the venturi. If necessary,
tighten the clamp.
Make sure that the non return valve can
move freely. If necessary replace the non
return valve.
Check, after each fix, if the error reappears.
If the error reappears continue in finding
the cause.
- Measure the pressure differential
across the air proving switch, refer to
Air pressure differential (see 8.9.2).
Venting system (see 8.7):
- Make sure if the venting system is
compliant.
- Make sure that the venting system has
no blockages.
- Make sure if the air inlet screen has no
blockages.
Condensation discharge:
- Make sure the condensate drain has
no blockages.
- Make sure that the condensate drain is
connected to the waste water
discharge by an open connection.
Burner:
- Make sure that the the burner is clean
(see 11.4.1).
- Measure the pressure differential
across the air proving switch again. If
the pressure differential is insufficient,
clean the heat exchanger.
- Make sure that the air proving switch
is closing, by using a multimeter.
Installation, Maintenance and Service part