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- 27 Mar 2007
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I have installed a secondary return on a gravity hot water system and am struggling to get it to circulate. innitially I installed the grunfos bronze pump with the anologue time clock but was informed by tech support that this was used for mains pressure systems and that it wouldn't work on my system.
I was adviced by tech support to get hold of a 1550b or 1560b bronze circulating pump which I have now done and it has been installed as per manufacturers instructions.
It is on the secondary return pipework just beside the cylinder in the vertical plane pumping down into the cylinder and up out of the top and round the hot distribution pipe work.
It seems to work for a while and then stops circulating for no apparent reason. It is also noisier than a usual circulating pump. This I believe to be air and I have tried to eliminate all air by bleed the pump through the slotted screw on the front.
Should I also fit AAV's at the high point on the secondary return loop at the last draw off. If it is air how do I get rid of it. When I went back to the pump after an hour or so the pump is red hot but the pipe work is not ie no circulation.
As it happens I am about to change it over to an unvented system and so will be re piping the secondary return back into the cold feed and replacing the original bronze pump with integral mechanical timer but would appreciate any advice on secondary returns on gravity systems as I have run out of ideas
??
I was adviced by tech support to get hold of a 1550b or 1560b bronze circulating pump which I have now done and it has been installed as per manufacturers instructions.
It is on the secondary return pipework just beside the cylinder in the vertical plane pumping down into the cylinder and up out of the top and round the hot distribution pipe work.
It seems to work for a while and then stops circulating for no apparent reason. It is also noisier than a usual circulating pump. This I believe to be air and I have tried to eliminate all air by bleed the pump through the slotted screw on the front.
Should I also fit AAV's at the high point on the secondary return loop at the last draw off. If it is air how do I get rid of it. When I went back to the pump after an hour or so the pump is red hot but the pipe work is not ie no circulation.
As it happens I am about to change it over to an unvented system and so will be re piping the secondary return back into the cold feed and replacing the original bronze pump with integral mechanical timer but would appreciate any advice on secondary returns on gravity systems as I have run out of ideas
??