heatline solaaris 30?

Any body have 2 radiators ( both downstairs)which are hot at the TOP but cold at the bottom !!!-- bleeding the rads has no effect . How can you tell if the pump is running ,and what are the marks and switch ,which are on the pump? The system keeps losing pressure . I top it up to 1.5 Bar ,but the pressure is down to 0'8 the next day . Its been in for 5 years and has given constant problems