noisy pump

[gaffer]

I have a wilo gold 50 pump on my central heating system (standard gas fired back boiler and hot water tank) set to position 3

the pump has started making a funny noise that sounds like it could be a faulty bearing or maybe an airlock I guess

I have loosened the drain screw on the pump and water comes out

the noise is very faint when pump is set to 2 and non existent when pump is set to 1

I suspect the pump might need replacing but on the other hand the radiators all seem to be getting hot so the circulation seems ok

I have turned the pump down to 2 and will see if there is still suffient flow to heat all the radiators

the system is relatively old but the pump seems quite new and the hot water / central heating selector valve was changed a couple of years back

there have been no other changes to the system recently

had a good look through the old posts but there does not seem to be much on here about pumps, but forgive me if this question has been asked before.

Cheers

 

[wilhelm]

could be pump.

could be blocked cold feed.

 

[gaffer]

i checked the cold feed by tying up the ballcock in the feed tank and draining some water from a radiator

I did see the water level in the feed tank drop so I guess there is no blockage

so I guess it's time to change the pump

 

[bab]

If u do buy a new pump buy a Grundfoss 15-50.

 

[Agile]

Slow down!

Most pumps are noisy on speed 3 setting !

The system should work perfectly well on speed 2 setting !

I am sure the pump is fine from what you have said.

The Grunfoss pumps have a very hard bearing and are more tolerant of dirt in the water. They do seem to me to suffer from more electrical failures though.

The Wilo pumps are somewhat cheaper but have a plastic bearing which is fine as long as the water is clean. They hardly ever have electrical failures though.

You pay your money and takes your pick!

In your case I dont think anything needs to be changed!

Tony