Singing noise related to water pump

[benaround3]

Since our central heating system was upgraded in October we have noticed a singing noise in the house when the water circulating pump switches on. It is a new Grundfos UPS2 15-50/60 pump with 3 speeds. Reducing the speed reduces the noise but it doesn't go away, and we need to use the maximum speed to heat the house effectively.

The noise sounds like a musical tuning fork. It comes from any part of the house where there are pipes or radiators, as well as from the pump, but is not easy to pinpoint. It is not loud, just annoying. How loud it is depends on where you are in the room and what direction your head is turned. It is as though the noise from the pump transmits to the water everywhere in the system.

The system works well otherwise, there are no other clues, although there is a slight unrelated whistling from the boiler flue which is being investigated.
A Magnaclean filter was fitted and has removed about a cupful of black rust already.

 

[oldbutnotdead]

Copper pipes presumably? How is the pump supported- a couple of these https://www.toolstation.com/anti-vibration-circulating-pump-bracket/p37290 will make a difference

 

[benaround3]

Yes, copper and the heating engineer didn't use a lot, so there is an indication for using these, but on the other hand when you hold the pump tight or hard up against a firm object, it doesn't reduce the noise at all. The engineer is returning soon I hope and has talked about replacing the pump with a Wylie.

 

[benaround3]

Problem solved. Singing noise completely gone. Plumber replaced the Grundfos with a DAB 40-70/130. Whether the Grundfos was faulty or there was an incompatibility with my system we will never know. Thanks for all support.