A7 — Hot water sensor defective

What does A7 mean?

The domestic hot water (DHW) negative thermistor coefficient (NTC) sensor or its connecting leads are defective. This will affect the boiler's ability to provide hot water.

• Defective hot water NTC sensor.
• Damaged or loose connecting leads to the sensor.

Click steps to track your progress.

1. 1

   Check the wiring connections to the hot water NTC sensor for tightness.

2. 2

   Inspect the sensor leads for any signs of damage or corrosion.

3. 3

   Reset the boiler by pressing the reset button, or power cycle it at the mains.

4. 4

   If the fault persists, contact a Gas Safe registered engineer.