A.O. Smith SGS - 100 Installation & Service Manual page 84

Code + Description Cause
F03 (lock out error) Damaged wiring/Open
circuit
The pressure switch
fails to work correctly
Pressure switch not
closing
Instruction manual SGS
Solution
1. Check the wiring between the pressure switch and the
controller
2. If necessary, replace the wiring
1. Check the running speed of the fan
appliance")
2. Check that the hoses on the pressure switch and the air supply
hose between fan and burner are correctly fitted. Refit them if
necessary
3. Check for cracks in the hoses on the pressure switch and in the
air supply hose between fan and burner. If necessary, replace
the hoses.
4. Check that the flue gas outlet is compliant
flue").
5. Check for blockage in the flue gas discharge. Remove any
blockage that may be present
6. Check for blockage in the condensation water discharge.
Remove any blockage that may be present.
7. Measure the pressure differential across the pressure switch.
See the table in Preparation for
maintenance (15.2 "Preparation for
insufficient pressure differential, clean the heat exchanger. If the
pressure differential is acceptable, check that the pressure
switch is closing, using a multimeter.
Remark
If the error cannot be resolved or is persistent, contact your
installation engineer
To replace the necessary parts, you must contact your installation
engineer
(12.5 "Display the selected
(3.10 "Air supply and
maintenance"). If there is
is
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