Ferroli Modena 80E Losing pressure?
 
                Hi, please can you advise?  When the CH is used the pressure gradually reduces over a period of a couple of days, and then the system wont run.  I have replaced the relief valve which was definitely faulty, and now the pressure holds up for much longer now - a couple of weeks.  Is the expansion tank likely to be faulty?  What pressure should it be charged to?
            
             Norman John
            
 July 2006