I,m having a problem with my Grundfos negative head pump.It supplies an upstairs bath and sink with hot water only (it,s a single impeller pump amazon 3 bar).The problem is that there is a very long delay before the water comes out from when the tap is turned on, as long as five minuets somtimes this gets less the more times the tap is used.The pump is only a few weeks old and worked fine when initially installed,can anyone shed some light on this problem.The taps are mixer type and the cold water is mains fed and works fine, there was a pressure equalising valve fitted but this was removed but the problem still persists.Any help welcomed.
Grundfos negative head pump
- Thread starter NACD
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Thanks for your prompt reply doitall.
No this is what is strange as I understand it as soon as there is a drop in pressure ie opening the tap the pump should kick in.If there was a lack of water in the system would the pump be running all the time?.
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Thanks again for your quick reply doitall ,I have been in touch with Grundfoss and they have told me that I can adjust the pressure switch slightly although its a bit fiddly.They also told me that the pipe run from the pump to the outlets may be to long.I will try the pressure switch and check for air as you suggested and hope this resolves the problem.
Let us know how it goes for future references.
Hi doitall I adjusted the pressure switch as per Grundfos instructions (it is a bit fiddly but not that difficult)and the taps are now working almost instantly when they are opened.The pressure switch has a small adjusting screw which you turn using a allen key / torque key you have to be quite precise because if you turn to much the pump will fire all the time to little and you get the delay .Thanks again for your help and advice DIYnot Local
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