I had the same problem and had to buy and replace a new heater.  I got the part from ebay, cost 45.00 but it was a nightmare to replace, it took me 2 days as you have to strip the whole machine down to get into it.  I would advise you to get someone else to do it.  Mine was working fine but now the on/off switch is away on it but this looks simple to replace.
                 Agnes
                
 May 2007