Hi

Would appreciate some advice....

After earlier draining the heating system, I now have a load 'drilling' sound from the pump. All radiators bleed with system off. Tried removing the screw on the front of the pump to bleed, but only a very slight dribble of water came out. The pump is only a couple of yrs old, and has always been slightly noisy. Noise loader when speed increased. We can hear it all around the house when running.

The pump is securely mounted.

I guess there is still air in the system......

Should I end up replacing the pump, anyone recommend a SUPER quite/silent one?

Cheers for your help!

Try bleeding the system and pump with the power turned off, turn back on for a few minutes and then repeat the process again.

Mog

Try bleeding the system and pump with the power turned off, turn back on for a few minutes and then repeat the process again.

Mog

As above, it may help if two people work on this, if you have a ladder style towel warmer, or the highest bleed point in your house, As Mog's states but first open the highest bleed point, then the pump. The head of pressure should force the air out at the pump. Grundfos are as good as any in my book...

Good luck :thumb:

Thanks for the tips guys. I'll have a go this morning....

The pump woke everyone up this morning - early!

I'll let you know how I get on....

Last time I had this the pump rotor had sheared.

I have 3 star cover, so the gas man came out and replaced it FOC.

I hope it is not that.

Mmmm....

I have followed the instructions. A small amount of air came out, but not much at all.

Pump still noisy.

Help.

usually helps if the pumps mounted vertically
sometimes even though they are new they dont last long
seems to be the luck of the draw with pumps

Thanks steppers.

The pump is mounted vertically.

It appears that the rad in the loft room is about the same height as the expansion tank....??? I wonder if this could be contributing?

Thanks!

Did the loft rad work before, the cold feed and vent positions are very important when a rad is that close in height to the expansion tank.

Mog

Yes Mog, the loft rad has always worked OK. In fact all worked OK really. Leaving the pump off at the moment, just too noisy!

try loosening the top 22mm nut above the pump valve this usually releases a bit of air the screw doesnt ;)

Thanks very much easyscoob. I'll give it a go when I get hold of some large adjustables.

Cheers.

Replace your pump....simple as that...

Why would the pump fail after drain and re-filling the system?

Cheers

No particular reason but its a mechanical part thats prone to wear. you say at the beginning of your thread it was noisy to start with thats a clue its possibly on it way:turn your heaing /water off vent all radiators and vent the manual vent on your hot water pipe going to your cylinder(if possible try and put your diverter valve in the manual/flushing position) if every things got water there and the pumps still noisy new pump rqd id say (ps release diverter valve to rest position)

Time for a new pump I think, bear in mind though that the pump uses the heating water for lubrication and sometimes the bearings don't like being exposed to air.

Mog

Thanks for all your help guys.

Bit the bullet and bought a new Grundfos pump, as just could not release the air in the Cosmos pump.

Well..... Sorted! So far so good. Air cleared really easily from the system and pump. Dead quite.

See if it stays that way!