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FAULT 7
Control Panel Failure
5 seconds – seven 1 second flashes - 5 seconds
Before the start up sequence commences the PCB carries out a functional check of the
potentiometers (temperature controls), if a fault is detected within 5 seconds, the ignition
sequence will not take place and lock out will be displayed.
POSSIBLE CAUSES
Faulty potentiometer
Faulty PCB
FAULT 9
1. Residual Ionisation Signal
2. Gas Valve Control Circuit Failure
5 seconds - nine 1 sec flashes - 5 seconds
1. Residual Ionisation Signal
The most common cause of F9 is due to the P.C.B. detecting an ionization signal after the
gas valve relays have closed CORRECTLY.
There are a various reasons why the ionization signal continues to be produced after the
gas valve has closed:
1. A high residual temperature within the combustion chamber
2. The distance between the ionization electrode and the burner being too short (see
below)
3. Environmental conditions such as supply voltage or humidity
Extensive testing has determined that if the boiler has failed with F9 and the gas solenoids
are working correctly, potential reoccurrence can be avoided by replacing the ionization
electrode with a modified version featuring a reduced length of porcelain insulation.
All new electrodes have a porcelain length of 45mm and should be set at a distance of
between 7mm and 10 mm above the burner.
Older type electrodes which could potentially detect a residual ionization signal have a
porcelain length of 55mm and should be set at a height of 13mm above the burner to
reduce the risk of the fault reoccurring.
Replacement to the new type electrode is strongly recommended as soon as possible if
the boiler has faulted to F9.
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