Slow radiator warm up, or even never getting hot is probably caused by sludge in the radiator and piping system. This can be corrected by a powerflush. Metallic and other residue is collected by a filter in the flushing system so is not sent down the drain to cause problems elsewhere. No mess is caused and the result is a fully working and efficient central heating system. An in line filter can also be installed to prevent a recurrance of the problem. You have to pay for all the water you use if you have a meter.
