loosing water

my mums pulsa coil 2000 ran dry. what a daft idea in an old peoples home she has to stand on a chair to fill it. i have topped it up about 2 litres a day for a week and it still keeps needing more. there is no water on the floor and no smell of damp. the green light doesnt work but reading other peoples feedback the bulb could have gone. the boiler works ok, just wondered if we are filling an expansion tank or something similar. there is no bleed valve as per drawing. any ideas please

what you could do is see if any corrosion at the elements, by looking under the electrical covers, i have known water to esape

Turn all the power to the unit off, remove the main unit cover and visually inspect for leaks throughout the unit. If you see the body of the cylinder is leaking, then replace the entire unit, if it is only the elements leaking, then replace them.

Pulsacoil Replacement