48
FAULT FINDING
F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING F
AUL
T FINDING
IMAX XTRA EL
-
Installation & Servicing
61 THERMISTOR FAULT
Fit a new thermistor
no
Disconnect the electrical connection to the Flow/
Return/Heat Exchanger thermistor as required and
check the resistance using a suitable multimeter
connected across the thermistor's terminal pins.
At 25°C expect 9,700 - 10,300
Ω
At 60°C expect 2,400 - 2,600
Ω
At 85°C expect 1,000 - 1,100
Ω
Is the thermistor value correct?
yes
Check and replace wiring as necessary
Replace main PCB
no
yes
Is there continuity between the PCB and the thermistor?
62 OUTSIDE SENSOR FAULT
Fit a new Outside Sensor
no
Disconnect the wires to the Outside Sensor. Check the
resistance using a suitable multimeter connected across
the thermistor’s terminal pins.
At 0°C expect 32,000 - 33,000 Ω
At 10°C expect 19,000 - 21,000 Ω
At 20°C expect 12,000 - 13,000 Ω
Is the thermistor value correct?
yes
Ensure the wiring has continuity and is
securely connected
no
Does the Outside Sensor wiring between the boiler
terminal strip and the PCB have continuity and is it
securely connected?
yes
Replace main PCB
Securely connect the wiring at both
the boiler and Outside Sensor
no
Is the wiring securely connected at both the boiler and
Outside Sensor?
yes
