I have a potterton kingfisher cf 50 boiler.My up stairs ch rads is fine but down stairs one of them is warm nd other two are few days stay cold and after few days three of them gets hot again and so on.is this boiler problem or ch rads? What can I do to fix it? I have a one year old at home.plz help.and thank you in advance.

Rumi, December 2013

look like system need good clean up ,add boiler cleaner in header tank ,drain boiler before adding ,follow what on ,run for week ,drain out open radiators valves ,and air vent to flush out ,close all air vent ,refill system ,add restorer ,in header tank , take air out one by one ,and balance system ,close half the one hotter ,full open which are not

ltd, December 2013