Grundfos UPS2 for UPS3

[Tom5099]

I have a Grundfos UPS2 fitted and its become very loud humming when heating comes on, airing cupboard outside bedroom so not ideal
It stops after 15mins as the waters warmed up so my thinking is the pumps on its way out?

When fitting the Grundfos UPS3 are people leaving it on the factory setting III or are we putting it back to the II as we did with the UPS2, not keen on keeping using the moduaoting flow on the new pump as seems daft with a modulating boiler

my system is a unvented system with boiler and tank

Thanks in advance

 

[John.g]

Speed 3 on that pump would be overkill for any normal system as its 6.5M, even speed 2 at 5.2M is very powerful, speed1 at 4.2M should be satisfactory IMO, reason being that the pump still runs in a constant pressure fashion for some of the flow requirements, not like real (old) fixed speed pumps.
Constant pressure CP1 at 3M should be a good choice.

It is recommended to run on speed3 for is it 10 mins? to vent air from the pump.

 

[John.g]

You can see the pump curves/output here.

 

[Tom5099]

Speed 3 on that pump would be overkill for any normal system as its 6.5M, even speed 2 at 5.2M is very powerful, speed1 at 4.2M should be satisfactory IMO, reason being that the pump still runs in a constant pressure fashion for some of the flow requirements, not like real (old) fixed speed pumps.
Constant pressure CP1 at 3M should be a good choice.

It is recommended to run on speed3 for is it 10 mins? to vent air from the pump.

That's great thank you, I will run it at setting 2 and see how it goes, do you agree the pump needs replacing with it humming loudly until it gets warm and then stops bene loud?

the system is a new build so 22mm manifolds with 10mm to all the radiators

 

[ShaunCorbs]

If it’s working I would just buy a pump to swap when it goes

 

[Tom5099]

My only issue is the airing cupboard is outside baby's bedroom and hums and vibrates very loud when starting up until it gets warm.
I have ordered the UPS3 and will set it at setting 2 and hope it sorts the noise out

 

[JAMES English]

I have replaced my old UPS 2 universal pump with a UPS 3. Although when the central heating is on (pump setting 1) the system works find but when i put the hot water on with or without heating i have air gussying around the system and there seams to be a little "back pressure" and when i shut the hot water off i need to bleed some radiators. this as resulted in that i have to rely on my immersion heater for hot water.
p s never had this problem before changing the pump.
Would be grateful for any advice

 

[John.g]

Presume OV system, the UPS3 is a very powerful pump even on speed 1, any idea on what speed setting the UPS2 was on?.
I would suggest changing from pump setting 1 which is 4.1M to constant speed 1 (CP1) which is 3M, this may cure your problem and still give adequate flow rates.

Also ensure the pump has been installed correctly orientated.