Boiler and heating issue ,boiler less than 3 year old ,minor issue

Sludge in radiators effecting heating and hot water upstairs to shower and bath

My boiler is a IDEAL it keeps flashing F L the book says push reset button keep doing that but won't stay lit ???? Need a cheap fix please

Power flush on micro bore pipes

I need someone to reset our electric radiator timers

Bay and new combi boyler installed