Recently (just before Christmas) descaled central heating using Fernox DS-40, flushed system out with neutraliser plus three flushes of cold water. Refilled system, added inhibitor (hard water area).
System is working fine now.....EXCEPT:
The pump (Grundfos, three years old, don't have the model number to hand, sorry) constantly makes a "ticking" noise (sounds a bit like loose ball bearings rattling around, though I hope it isn't that!). When the heating switches off the pump makes a sort of "whooshing" sound (like sand running down a pipe). This happens regardless of pump speed.
The system is pretty air free as far as I can see (I've bled it quite a few times, all the rads are hot all the time).
Could this still be sludge in the pump/system? (Shouldn't all the flushing have got rid of it?) Or am I looking at something more serious?
System is working fine now.....EXCEPT:
The pump (Grundfos, three years old, don't have the model number to hand, sorry) constantly makes a "ticking" noise (sounds a bit like loose ball bearings rattling around, though I hope it isn't that!). When the heating switches off the pump makes a sort of "whooshing" sound (like sand running down a pipe). This happens regardless of pump speed.
The system is pretty air free as far as I can see (I've bled it quite a few times, all the rads are hot all the time).
Could this still be sludge in the pump/system? (Shouldn't all the flushing have got rid of it?) Or am I looking at something more serious?
