DHW Sensor Open.
1. Be sure the DHW Tank Sensor (54157), provided with the boiler, is connected to terminals #5 & #6.
2. Remove the wires from terminals #5 and #6 on the boiler and check the resistance between them.
- If the resistance is above 10 k Ω, check the resistance at the sensor.
- If the reading at the sensor is the same, replace the sensor.
- If the reading at the sensor is lower, replace the wiring.
