H.....3..... (DHW THERMISTOR ERROR)
Is there continuity between the
PCB and the thermistor ?
Remove the boiler DHW thermistor from the plate
heat exchanger and disconnect thermistor wires.
Are the thermistor values correct ?
Check resistance using a suitable multimeter
connected across the thermistor’s terminal pins
At 25 oC expect 9,700 - 10,300 Ohms
At 60 oC expect 2,400 - 2,600 Ohms
At 85 oC expect 1,000 - 1,100 Ohms
No = Replace the thermistor
YES
Is there continuity between the
PCB and the thermistor ?
Yes
Replace PCB
No
Check and replace wiring as necessary.
SD, March 2012
