Problem with new Grundfos UPS

[Jerry]

Hello everyone,

I have a problem, to which there is probably a simple solution but I can't see the wood for the trees.

I swapped out an old Grundfos pump for the new one. Gone is the lovely old silver button on the front where you can bleed the pump and now we have more bells and whistles. But that's OK because the government says they are more energy-efficient and the homeowner (and polar bears) are looking forward to the amazing energy savings they are going to make!

Anyhow, the entire blood house is vibrating. You can hear the pipes vibrating, the rads vibrating and anything touching the pipes vibrating. The homeowners say its worse when the system is warming up but it can happen randomly when the system is running. The entire household is woken up by this in the morning. FML

The system is open vent and all rad valves are bi-directional (TRV4's). It's an old system and boiler and was powerflushed about 5 years ago.

This problem did not happen before. The pump, however, is not very well supported with clips etc and the additional pipework around the cylinder is also not very well clipped in

My first response was to turn down the pump but then the boiler thermal cut out gets involved and ruins the party. The homeowners cannot reduce the heat output of the boiler because otherwise, the property does not heat up.

I guess the best option would be to add a boat load of pipe clips and possible re-route some pipework but this is a lot of money (and time) the homeowner does not want to spend. After all, it was only a simple pump swap.

My second plan is to swap the Grundfos for something else. Maybe the weird harmonics will be different with a different manufacturer.

Anyone else got a better idea, please?

Many thanks,

J

 

[John.g]

Can you post the exact model number and setting of the new pump please and if possible the make/exact model number of the old pump and ideally its pump setting and then can advise to the nearest setting for the new pump.

 

[Jerry]

New - Grundfos UPS3 and on power lvl 3
Old - Grundfos UPS 15-50 (I think)

 

[ShaunCorbs]

Rubber lined clips either side of the pump would be my first port of call

 

[Jerry]

Rubber lined clips either side of the pump would be my first port of call

Ha! Got some on the van!

Good Call

 

[Scott_D]

was it the exact same length?
Could it be a little longer/shorter and now the pipe is pushing against a noggin or joist under the floor?

 

[John.g]

There are different types of the UPS3 including the UPS3 Alpha model B but assuming just the link I have to a UPS3 the setting 3 will give a pump head of 6.5 meters between 0 flow and 1.3 m3/hr=22LPM, setting 2 is a 5M head betweem 0 flow and 1.1 m3/hr=18LPM and setting1 is a 4M head which is a 4M head between 0 flow and 0.4 m3/hr=7lpm.
I would suggest changing to fixed speed 2 and see if problems persist, setting 1 would seem a bit on the low side but you can try it as you may have a very well installed low loss system. If you have any Alpha variation then please repost.

 

[Jerry]

There are different types of the UPS3 including the UPS3 Alpha model B but assuming just the link I have to a UPS3 the setting 3 will give a pump head of 6.5 meters between 0 flow and 1.3 m3/hr=22LPM, setting 2 is a 5M head betweem 0 flow and 1.1 m3/hr=18LPM and setting1 is a 4M head which is a 4M head between 0 flow and 0.4 m3/hr=7lpm.
I would suggest changing to fixed speed 2 and see if problems persist, setting 1 would seem a bit on the low side but you can try it as you may have a very well installed low loss system. If you have any Alpha variation then please repost.

My first response was to turn down the pump but then the boiler thermal cut out gets involved and ruins the party. The homeowners cannot reduce the heat output of the boiler because otherwise, the property does not heat up.

 

[John.g]

Should have read your original post properly, This pump may also have constant pressure (CP) settings but in general I find that Grundfos don't give the user a wide range of CP (or PP) settings.
I have a Wilo Yonos Pico 6M pump which apart from the traditional 3 speed settings offers a constant pressure (CP) mode and a proportional pressure (PP) mode which range from 0.5M to 6M and can be incrementally adjusted in 0.1M steps, I run mine on a PP setting of 4M.
Of course your problem may be "mechanical" like post #6 suggests but if you can post a link to your installed pump model it would be interesting as there are lots of posts on various sites that discuss problems when changing out circ pumps, especially on vented systems like mine.

 

[Jerry]

was it the exact same length?
Could it be a little longer/shorter and now the pipe is pushing against a noggin or joist under the floor?

Grundfos says they are a 'like for like' replacement
[automerge]1576426942[/automerge]

Should have read your original post properly, This pump may also have constant pressure (CP) settings but in general I find that Grundfos don't give the user a wide range of CP (or PP) settings.
I have a Wilo Yonos Pico 6M pump which apart from the traditional 3 speed settings offers a constant pressure (CP) mode and a proportional pressure (PP) mode which range from 0.5M to 6M and can be incrementally adjusted in 0.1M steps, I run mine on a PP setting of 4M.
Of course your problem may be "mechanical" like post #6 suggests but if you can post a link to your installed pump model it would be interesting as there are lots of posts on various sites that discuss problems when changing out circ pumps, especially on vented systems like mine.

https://www.NoLinkingToThis/p/grund...0v/503fh#product_additional_details_container

 

[John.g]

A bit strange that if you turn down the speed from 3 to 2 because you will/should still be pumping the same or more than the original pump on speed setting 3 (if it was set to this) or you should still be pumping at a flowrate of 88% of speed3 on the new pump, you also said speed 2 operates the boiler thermal cut out which again is a bit strange because if its a gas boiler then it should modulate down and if a oil fired boiler the temperature has to reach > 110C to operate the trip.
Even if the pump was installed "wrong way round" it still shouldn't cause vibration, the only other reason (apart from a faulty pump) is that there is air still trapped in it, the attachment shows to vent it, I think it just keeps changing the pump speed over the purging period but you may have done this previously anyhow.

Another problem with these A rated pumps is that "fixed speed" mode actually isn't, your pump maintains a 6.4M head between 0 flow and 1.1m3/hr(18.3LPM) so if a ABV is fitted it has to be indexed to pass the minimum at all times, a true fixed speed pump head falls as soon as there is any flow so relatively easy to set up the ABV. You may also find that the ABV (if fitted) will still pass when fully closed, you might check its setting and then maybe run on speed2 with the ABV ~ on index setting at 0.45 ish.

 

[oz-plumber]

Before going too far into the pump setup and installing a load of extra clips, I would go around and check the TRV's.

The old pump may have died a slow death.
The new pump may have activated something that was not noticed with the old weaker pump.

The sounds you're describing sound like valve(s) chattering.

 

[John.g]

Or (temporarily) stick back in a old but working Grundfos 15/50 and see what happens?.

 

[doitmyself]

There are different types of the UPS3 including the UPS3 Alpha model B

There are, currently, two separate ranges of Grundfos domestic pumps: Alpha and UPS. The Alpha range consists of the Alpha 1 and Alpha 3; the UPS range of the UPS3.

There is also the UP/UPS Series 100 range of large pumps (up to 10m³/hr and 10m head) which are intended for schools, hotels and hospitals etc. It also includes the 8m version of the UPS2.

 

[John.g]

The replacement pump would seem be a reasonable "fit" for the original but speed 2 which = speed 3 on the 5 m pump isn't adequate and trips the hi limit stat on a gas fires boiler.

 

[doitmyself]

The replacement pump would seem be a reasonable "fit" for the original but speed 2 which = speed 3 on the 5 m pump isn't adequate and trips the hi limit stat on a gas fires boiler.

It would help if we knew which boiler the OP is talking about. Then we would, at least, know the flow rate.

 

[Ian Leslie]

just fitted a grunfos ups3 pump as a replacement. It seems to be running but water is not being circulated, whatcould be the problem?

 

[ShaunCorbs]

Pump valves open ? Air lock run hot water only ?

 

[John.g]

Which of these settings is it on?, note the LEDs positions and some may be flashing.