It sounds like you may have a faulty flow valve. A replacement part can be purchased direct from Mira Customer Service on 0844 571 5000 or you could book one of their Engineers to repair at a fixed price
Rob
July 2010
Automatic Answer
While you wait for answers, we may have found some information which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix plumbing.