Do I need to reset Pulsacoil III after re-filling tank?

I've lived with the Pulsacoil III for 5 years and roughly every six months the water level in the top tank drops and triggers the boiler to turn itself off. Previously I've had an engineer come round and fix it but after reading a very helpful website (thank you Mike the boiler man!!) I've decided to try and remedy the problem myself.

All lights on the front of the boiler have switched off, when usually there are one or two green lights on (it does vary, sometimes one on, sometimes two!!), the water is cold and the level of water was too low. Having filled up the tank to the correct level the lights have not come on and the water is still cold. I'm assuming the boiler does not reset itself so I need to know how I can do this.

Anyone know?

Many thanks in advance.

There is a brown button near the neon light, just push that in. That will reset the overheat stat