IDEAL Logic Combi ES ES24 User Manual page 57

77 ALTERNATING 'F' AND '3' - FAN FAULT
Does the wiring from the Fan to the PCB have
secure connections at both ends and has not
deteriorated? Does the wiring have continuity?
Is there 230Vac at the Blue and Brown connections
to the 3 way connection on the Fan?
78 ALTERNATING 'F' AND '4' - THERMISTOR FAULT
Is the wiring securely connected to the Flow Thermistor
(located in the top of the Heat Exchanger?)
Disconnect the wiring from the Flow Thermistor
Check the resistance using a suitable multimeter connected
across the Thermistor's terminal pins.
o
At 25 C expect
o
At 60 C expect
At 85 o C expect
Is the Thermistor value correct?
Is the wiring securely connected to the low voltage 6 way
connector at the front left hand side of the PCB?
79 ALTERNATING 'F' AND '5' - RETURN THERMISTOR FAULT
Remove the Return Thermistor from the CH Return
Pipe and disconnect the wires.
Check the resistance using a suitable multimeter
connected across the thermistor's terminal pins.
At 25 o C expect
At 60 o C expect
At 85 o C expect
Is the Thermistor value correct?
Is there continuity between the PCB and the Thermistor?
Logic Combi ES -
Installation and Servicing
Fault Finding
YES
YES
9,700 - 10,300 Ohms
2,400 - 2,600 Ohms
1,000 - 1,100 Ohms
YES
9,700 - 10,300 Ohms
2,400 - 2,600 Ohms
1,000 - 1,100 Ohms
YES
YES
Replace PCB
NO
Rectify Wiring &
connections
NO
Replace PCB
YES
Replace Fan
NO
Securely connect the wiring to the Water
Flow Thermistor
NO
Fit a new Thermistor
NO
Securely connect the wiring to the PCB
Replace PCB
YES
NO
Fit a new Thermistor
NO
Check and replace wiring as necessary
57