hi i have an ideal classic boiler with honeywell controls(cylinder stat,room stat,controller and three port motorised valve.I have recently noticed that the down stairs rads are alot cooler compaired to upstairs,and that the 3 port valve is in the manual position i returned it to auto which made no difference.my programmer cannot select ch seperately if i turn the cylinder stat down and the room stat up the boiler and pump stops should this be the case.I also seem to get alot of air in the system bleeding the rads makes little difference,could a faulty valve cause the lack of heat in the downstairs rads.