John, You could try asking Kevin Ground at RNIB Peterborough if he's marked any combi systems. As I understand it, it's only aligning the pressures which may be impossible, but you don't need to do that very often. Richard Godfrey-McKay ** To leave the list, click on the immediately-following link:- ** [mailto:access-uk-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** access-uk-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:access-uk-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** access-uk-request@xxxxxxxxxxxxx with the Subject:- faq