I have a open vented pumped central heating system connected to a
Netaheat Electronic conventional boiler. I recently decided to give it
a cleanout so put some fernox cleaner into the system. After flushing
the system out and re-filling, the boiler now makes 'gurgling' noises
when the burner is on and for a short while after it shuts off (which
i assume to be air and/or hydrogen)
I have bled all the radiators and am only getting water out (and they
all get hot), plus tried opening slightly the vent situated just above
the output side of the pump (between the pump and the DHW cylinder) so
it dripped slowly and left like that for a day to see if that would
get rid of the bubbles - has not helped though.
The boiler also makes some kettling noises when the burner is on but
i've got some fernox noise reducer for that but do not want to put it
into the system yet until i know i'm not going to have to flush the
system out again.
Should the system eventually quieten down with the air bubbles
escaping through the overflow vent pipe ? or do i need to bleed the
system in some other way ? And if it should quiten down, how long does
this normally take ?