When a toilet seems to flush itself without being asked there is a water leak from the tank or cistern down into the bowl. Eventually enough water leaks out of the cistern and into the bowl that the water level in the cistern drops enough that the toilet fill valve opens to re-fill the...
(but quite out of sight); to which pipe you must have a cock or a washer, to yield water with some pretty strength when you would let it in.This cistern in the first plot is figured at the letter A; and so likewise in the second plot. The small pipe in the first plot at D, ...