GRUNDFOS BOILER PUMP EXTREMELY LOUD NOISE THEN OFF

[Nicetoseeyoutoseeyounice]

My Grundfos central heating pump has just made an extremely loud noise and I have turned it off, so, central heating and water is now all off.
It has been making a whirring and droning noise now for a while, I bled the pump by removing the silver screw in the middle and just water trickled out, no air, no debris.
I have 2 tanks in the loft and have checked the small one but really don't know what I am looking for.
I will take a pic and try to upload to here but in the meantime, when looking at the tank on the left side there is a thicker open pipe just above and bent over the tank, there is also an outlet on the opposite side to this, the ball cock seems movable, ie when I put a little pressure on it water started tricking in.
Somewhere on here I read 'is the water over the outlet pipe', do they mean the outlet pipe as in the overflow which comes out at the side of the house.
Your help would be much appreciated.

 

[stardanny]

Check the water in small tank got water.

Does the heating and hot water work okay?

Pump may be nearer end of live, worn out.

Daniel.

 

[Nicetoseeyoutoseeyounice]

Thanks for your reply. The small tank does have plenty of water in it although there is a fair bit of scum of the top.
The heating and water were working fine.
It didn't actually turn itself off, the noise scared the hell out of us so we immediately just turned everything off.

 

[stardanny]

On the pump, there is a switch, what number is it on? Try turn down to 2 or 1 and see what happen.

I think you need a new pump.

Daniel.

 

[Nicetoseeyoutoseeyounice]

The switch on the side was set at 3, this is how it was left when it was fitted and has never been touched, I have turned it down to 2 but not yet switched everything back on, to be honest I'm frightened it will blow up.

 

[stardanny]

It'll be fine. Switch back on and see what happen, does it quiet down?
When set on 2, some radiators may not come on or warm. Cos the pump speed is lower.

Daniel.

 

[Nicetoseeyoutoseeyounice]

Thanks, I will give it a go, do you think then the tank is ok as it is? should I try and scoop up the white scum at the top with a sieve?

 

[stardanny]

You can if you like

Daniel.

 

[Nicetoseeyoutoseeyounice]

I have turned the pump and central heating back on, the pump setting is on 2 and not 3 which is how it was set, the heating is working fine, but, the pump is still noisy, its not making that really loud screechy noise which vibrated right through the house but it is noisy, it also makes a bit of a whirring noise as though it can just about make it.
Is this debris in the pump, before this happened and it was just a little noisy I felt as though there was something in there, sludge etc, or am I just living in hope?
sorry for the delay but we have bled the radiators etc and had to wait to see if things warmed up etc etc.

 

[Nicetoseeyoutoseeyounice]

I have now had the heating on most of the day and rads are heating up fine, the hot water is also working, I have left the pump setting at 2, it is still quite noisy but not screeching, I turned it to 3 and it didn't screech but I have returned it to 2.
All the rads have been bled and tge pump has been bled.
Is it possible there is something inside the pump causing the noise, it's nice and warm but the droan throughout the house is now driving us all mad.

 

[stardanny]

You need to have the pump replaced.

Daniel.