A.O. Smith SGS-28, Installation, User And Service Manual

Page: 100 / 126

Code and description Cause Measure
F04 (lock out error)
Three unsuccessful
ignition attempts. No gas Open the main gas supply valve and/or
the manual gas supply valve before the
gas control valve
Check supply pressure to the gas control
valve
If necessary, restore the gas supply •
•
•
Air in the gas pipes Bleed the air out of the gas pipe (see
section 7.9.2) and measure the supply
pressure and burner pressure.
Defect in the hot surface igniter circuit Check that the hot surface igniter is
correctly connected (JP2).
Check the wiring of the hot surface
igniter.
Measure the resistance across the hot
surface igniter. This must lie between 2
and 10 Ohm (at room temperature).
Check that the hot surface igniter lights
up during ignition.
If necessary, replace the hot surface
igniter. •
•
•
•
•
Defect in the ionisation circuit Check that the flame probe is correctly
connected (JP2)
Check the wiring of the flame probe
Measure the ionisation current. This must
be a minimum of 1.5 microA.
If necessary, replace the wiring. •
•
•
•
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 signaled. Incorrect roof or wall flue terminal.
Recirculating flue gases. Check that the correct roof or wall flue
terminal has been installed (see section
7.7).
If necessary, install the correct roof or
wall flue terminal.
Check that the roof or wall flue terminal
discharges into a permitted area. •
•
•
F06 (blocking error)
Short circuit between
flame probe and earth Damaged cable in contact with metal
surface or bent flame probe. Check the wiring and the flame probe.
Replace the wiring and/or flame probe if
necessary.
Ceramic part of the flame probe is
broken/cracked. Check whether the ceramic part of the
flame probe is still intact, in the vicinity
of the air distribution plate of the burner.
If not the flame probe must be replaced. •
•
F07 (lock out error)
A flame has been detected
after the gas control valve
was closed. Defective gas control valves Check whether there is still burner
pressure present, after the gas control
valves have closed.
Check whether a flame is still present,
after the gas control valves have closed.
If this is the case, the gas control valve
must be replaced. •
•
•
F08 (lock out error)
Error message from safety
relay Flame detection before the gas control
valve opened. Reset controller.
If the error appears again, replace the
controller. •
•
F09 (lock out error)
Water temperature
protection. Temperature at the top of the tank
exceeds 93 ºC. Check that the circulation pump (if
present) is working
Check the position of temperature sensor
T
1
Reset controller
•
•
•
100 Installation, Maintenance and Service part