Grundfos pump humming

[dyrck]

Hi, my central heating uses a Grundfos UPS 15-50 which is about 15 years old. Over the last few months it has started humming, it's not very loud but in the wee small hours of the morning it resonates through the pipework and wakes me up.
The pump is mounted in the middle of a horizontal L shaped run of piping and if I push gently on the pipes the hum disappears but I can feel a light vibration.
Is it likely that the pump is knackered? I am loath to have a replacement fitted (UPS3 15-50/65 ??) just to find that a new unit vibrates and hums just as much.
What should I do?
Thanks for yor help

 

[Harry Bloomfield]

All pumps hum to some extent, made worse if they or the pipe presses against something resonant. See if you can push something between the pump/pipe to reduce the noise, like rubber.

 

[dyrck]

Trouble is the pump is a long way from any surface, with about half a metre of pipe either side of it. Perfect conditions to vibrate a little.

 

[Harry Bloomfield]

Trouble is the pump is a long way from any surface, with about half a metre of pipe either side of it. Perfect conditions to vibrate a little.

Then it needs some support added, to a firm surface. Could you wedge a piece of timber in between the pipe and a solid wall, to see what effect that gives?

 

[dyrck]

The nearest solid wall is a foot away from the pump. I'm wondering if I can put a wire stay in and effectively suspend the whole arrangement.

 

[Harry Bloomfield]

The nearest solid wall is a foot away from the pump. I'm wondering if I can put a wire stay in and effectively suspend the whole arrangement.

Suck it and see, it's just trial and error. Personally, I would start with the simplest fix and bit of timber just wedged lightly in between pipe and wall. Once you know what works, then make a more permanent job of it.

 

[TimboTwo]

Try rubber lined pipe clamps either side of the pump.

https://www.freewayfixings.com/product_guide/mobile/index.html#p=24
Other suppliers are available.

 

[dyrck]

Thanks to everyone for your help and advice.