49
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
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Installation & Servicing
63 FLOW/RETURN REVERSED
Check that the system pipework is correct
Reverse Pump
no
Is the Pump connected the correct way?
yes
64 CYLINDER THERMISTOR FAULT
Fit a new cylinder thermistor
no
Disconnect the wires to the cylinder thermistor. 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
Ensure the wiring has continuity and is
securely connected
no
Does the cylinder thermistor wiring between the boiler
terminal strip and the PCB have continuity and is it
securely connected?
Replace main PCB
Change menu setting for DHW Sensor
to “Switched Live” (See Frame 26)
no
Is a DHW Thermistor connected to the boiler?
yes
Securely connect the wiring at both
the boiler and cylinder thermistor
no
Is the wiring securely connected at both the boiler and
cylinder thermistor?
yes
yes
65 BCC FAULT
Securely attach the correct BCC for the
boiler onto the PCB. Note: ensure the
correct orientation of the BCC by placing
the side marked “TOP” upwards.
no
Is the correct BCC for the boiler securely inserted into
the slot at the front left of the PCB?
(identified by the label on the BCC)
yes
Replace the BCC with a new BCC (that is correct for the
boiler). After switching power on and resetting the boiler
does the fault disappear?
Replace main PCB
no