A7 and fault indicator LED are flashing.
(Boiler still produces hot water but at a lesser degree of accuracy over the temperature.)
Water NTC sensor defective.
Step | Check | Action | |
---|---|---|---|
1. | ▶ Check if the water NTC connector corroded, damaged or dirty. | yes: | ▶ Change relative parts. A7? go to step 2 |
no: | go to step 2 | ||
2. | ▶ Switch OFF the appliance. ▶ Disconnect the boiler power connection. ▶ Un-plug 20-pin connector from PCB. ▶ Check resistance from connections 3 to 4 on the cable side. Does the value match the ones described in table 39, page 36? | yes: | ▶ Connect the boiler electrical connection. ▶ Switch ON the appliance. ▶ Make a note of the altered service function settings (see table 4 on page 6) in order to keep the altered values. ▶ Switch OFF the appliance. ▶ Disconnect the boiler power connection. ▶ Change PCB control board. ▶ Reconnect the appliance power connection. ▶ Switch ON the appliance. ▶ Restore service settings previously noted. |
no: | go to step 3 | ||
3. | ▶ Un-plug NTC sensor from cable. ▶ Check resistance of NTC sensor. Does the value match the ones described in table 39, page 36? | yes: | ▶ Change the 20-pin connector lead assembly. ▶ Reconnect the boiler electrical connection. ▶ Switch ON the appliance. |
no: | ▶ Change NTC sensor. ▶ Reconnect the boiler electrical connection. ▶ Switch ON the appliance. |