38
classic m -
Installation & Servicing
FAULT FINDING
F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING
Does the pump setting give a differential
across the boiler in excess of 25 oC
Can the overheat condition be reset by pressing
the boiler reset button when the system is cold ?
Replace the system pump
Set CH control knob to maximum.
If the overheat trips again measure the flow temp:
Over 90
o
C
Check control thermistor
(
Refer to Frame 64)
.
Under 90
0
C
Replace overheat 'stat
YES
YES
Increase the pump setting.
Is differential now below 25
0
C ?
NO
NO
62 L.......A.........................(OVER HEAT)
Fill and vent the system and open all
isolation valves
YES
Is the boiler and CH system filled with
water and all isolation valves open ?
OK
NO
YES
NO
Replace overheat thermostat
60 L.....F.......(FLAME ERROR)
Check the ignition electrode and associated harness
for: continuity, visual condition
,
position
Are these functioning correctly ?
Check gas valve
wiring for
continuity
YES
Check the detection electrode and
associated harness for:
continuity, visual condition, position
Replace if necessary.
If the boiler reset button is
pressed does the boiler ignite for
a short time then extinguish?
Is 200 v DC supply
available at the gas valve ?
NO
YES
YES
Is 17mbar gas pressure
available at the boiler inlet ?
Replace PCB
Check gas supply
and rectify fault
Replace ignition electrode and associated
harness as necessary
NO
Replace gas valve
YES
NO
NO
61 L.....E......or
H.....E. (BOARD ERROR)
Code indicates internal fault
within the PCB
Replace PCB
Note.
Due the wave form of this rectified
voltage, the reading will vary
depending on the type of meter
used to measure the valve, (some
may measure the possible peak
voltage of 339 V). In general terms
a reading greater than 150 V
indicates that the correct voltage is
supplied to the gas valve.
Summary of Contents for Classic m3050
Page 1: ......
