Fault code lists this as ntc open cct. All checks out ok as far as I can see but the ntc is hard wired to the board so problematic to test. I’m assuming the board heater circuit has gone (as with so many of these boards), but never seen this model with the alarm codes b4. Is this likely to be the board or can then ntc be bought separately.
Board & NTC come together. The PCB has been altered a couple of times on these. Need full serial number to ID. One other slight problem 😥
The earlier board is over £50 list ex vat, the later one just over £20.00 but it does appear as though the latter needs an eeprom as well.