A: On plastic tanks rub a bar of soap into the split.

A: From a jewellers or a reputable electrical goods store. The battery number is 3V-CR2430.


  1. Switch the Watchman™ on and off. You will see a serial number followed by a lower case ‘R’ which stands for reset.
  2. Unscrew and remove the power tube wait for 2 minutes and then screw it back on. This should reboot the system.
  3. Within a few minutes the Watchman(tm) should display the level of oil in your tank.

A: F – Full
Red light flashing – No signal
Red flashing light – Tank is low on fuel
Fluid level low together with “BAT LOW” – New power tube needed
C – Connection fault replacement needed.


  1. Switch off Watchman™ display.
  2. Unscrew your existing copper tube battery from the transmitter.
  3. Pause for five minutes.
  4. Switch the Watchman™ display back on.
  5. Fit the new copper tube battery.