ChrisR: Thanks for the reply. Two more questions sprung to mind.
1.Could adding without flushing cause problems with the removed
scale/sludge effecting/blocking the radiators or the pump?
2. My system currently contains 100 (since August 1999).
Can I safely add the descaler/silencer to...
Our GLOW-WORM SAVER F boiler makes a whislting noise like that
of a kettle when set to a high setting (above 3).
The noise has steadily been getting bad over the last
year. I have set it to 2.5 and the noise is now bearable. It whisltes just
before it turns off. I understand that the...