A.O. Smith SGS - 100, Installation & Service Manual

Page: 85 / 110

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Instruction manual SGS 85
F04 (lock out error)
Three unsuccessful
ignition attempts.
No gas 1. Open the main gas valve and/or the manual gas valve supplying
the water heater
2. Check the supply pressure to the gas control
3. If necessary, repair the gas supply
To repair the gas supply, contact your installation engineer
Air in the gas pipes Bleed the air out of the gas pipe See Checking the supply pressure and burner pressure for how to
bleed air from the gas line, and measure the supply pressure and
burner pressure.
To replace the necessary parts, you must contact your installation
engineer
No burner pressure 1. Check the burner pressure to the gas control
2. Check that the gas valve(s) open and shut correctly
3. If necessary, replace the gas control.
Defect in the hot
surface igniter circuit
1. Check that the hot surface igniter is correctly connected (JP2).
2. Check the wiring of the hot surface igniter.
3. Measure the resistance across the hot surface igniter. This must
lie between 2 and 5 ohms.
4. Check that the hot surface igniter lights up during ignition.
5. If necessary, replace the hot surface igniter.
If the error persists, contact your installation engineer.
To replace the necessary parts, you must contact your installation
engineer
Defect in the ionisation
circuit
1. Check that the flame probe is correctly connected (JP2)
2. Check the wiring of the flame probe
3. Measure the ionisation current. This must be at least 1.5
microamps.
4. Replace the wiring if necessary.
Supply voltage too low Check the supply voltage, this must be 230 VAC (-15%, +10%).
F05 (lock out error)
Too many flame errors
have been signalled.
Incorrect roof or wall
conduit.
Recirculating flue
gases.
1. Check that the correct roof or wall flue conduit (3.10 "Air supply
and flue") has been fitted.
2. If necessary, install the correct roof or wall conduit.
3. Check that the roof or wall conduit discharges into a permitted
area.
If the error cannot be resolved or is persistent, contact your
installation engineer
Code + Description Cause Solution Remark