4.8 FLOW THERMISTOR FAULT
4.9 RETURN THERMISTOR FAULT
Pump Housing
Check the resistance using a suitable multimeter connected
across the thermistor’s terminal pins
Temperature
Resistance kΩ
25
o
C
9.7 – 10.3
60
o
C
2.4 – 2.6
85
o
C
1.0 – 1.1
Is the Thermistor value correct?
YES
Is there continuity between the PCB and the Thermistor?
YES
Replace PCB
Fit a new Thermistor
NO
Check and replace wiring as necessary
NO
Disconnect the wiring from the Flow Thermistor
Check the resistance using a suitable multimeter connected
across the Thermistor’s terminal pins.
Is the Thermistor value correct?
YES
Is the wiring securely connected to the low voltage 6 way
connector at the front left hand side of the PCB?
YES
Replace PCB
Fit a new Thermistor
NO
Securely connect the wiring to the PCB
Is the wiring securely connected to the Flow Thermistor
Located in the Flow Pipe lower LHS of Boiler?
YES
NO
Securely connect the wiring to the Flow
Thermistor
NO
Temperature
Resistance kΩ
25
o
C
9.7 – 10.3
60
o
C
2.4 – 2.6
85
o
C
1.0 – 1.1
59
Installation and Servicing
Section 4 - Fault Finding
FAUL
T FINDING
