Why is my new circulation pump twice as loud as previous model?

[Adam_and_the_boiler]

Hi all,

Let me start by saying, my heating works fine. I only know the basics of a system, and this may well be just me and my sensitive hearing...

I have been in my property for 5 years. I had a Wilo circulation pump, which purred wonderfully. I never took a photo of it as a reference, but it was of a green design, if that helps anyone. Last Christmas it sadly packed in. I had the pump replaced with a Grundfos UPS3 15-50-65. From the moment I put the heating back on afterwards, it sounded as if the pump was rumbling throughout and rattling through every pipe in the property. There'd be an enormous rumbled heard downstairs, beneath the airing cupboard; certain radiators would have brief rattling which seemed to come up to the thermostatic valves. It was a huge step up in noise when compared to the previous pump.

So after four calls and visits from the company who installed the pump, I gave up and got a second opinion. The second plumber suggested maybe the pump was too powerful for our system, and that he had a spare pump he could try in his van. It was a Grundfos UPS2 15-50/60, and looks very much like it's been used - however, it's certainly quieter. And I should be thankful for that. But! The pipes above and below the pump are very well braced; the pump itself emits a very deep, guttural rumble which, if I place a hand firmly against the side of the pump, can soften the noise somewhat. But I know it's still no where near as quiet as my old, Wilo pump.

I am not sure what I'm asking here; does this ring any bells regarding excessive rumbling from a pump/brand? Does it sound possible that my system cannot take a new branded pump? I'm not sure what I am hoping to achieve; I would just love the pump to be as quiet as it was before. For me, it makes the room the airing cupboard is in, unusable when the system is on.

I would be very grateful and interested in any feedback/thoughts, any of you fine folks can share on this. Happy to answer any questions/post images as best I can.

Many thanks,
Adam

 

[John.g]

What speed setting is this pump on?.
Also check direction of flow, if its on the boiler flow then the arrow should be pointing away from the boiler, if on the boiler return, should be pointing into the boiler.
If a sealed system where is the expansion vessel connected into the system.
a few pictures would help.

 

[Adam_and_the_boiler]

Thank you for taking a look, John. Much appreciated. I have answered as best I can below. I hope it's of some help!

What speed setting is this pump on?.

The lowest, speed 1.

Also check direction of flow, if its on the boiler flow then the arrow should be pointing away from the boiler, if on the boiler return, should be pointing into the boiler.

I believe it's on the boiler flow. The pump is upside down - as was my original Wilo one.

I have snapped these. Please let me know if they're not clear enough. I'm not sure how much of the pipes, etc, would help you evaluate any issue.

If a sealed system where is the expansion vessel connected into the system.

I'm sorry, I'm going to have to google the vessel. Above my knowledge!



Thanks again 🙂

 

[John.g]

The expansion vessel is a red cylinder but you may have a small tank in the attic as well as a bigger one.

For the moment see if you can take a photo of the pump setting, see below.

 

[John.g]

Sorry, I see you said above that its on speed 1, you could try it on proportional setting (PP) 3 by pressing the setting button for 5 secs the display should then change (to a flashing green LED) and just press the button briefly to iii (flashing). It may be a little weak for your system but just give it a try anyhow, its only a few button presses.

 

[Adam_and_the_boiler]

The expansion vessel is a red cylinder but you may have a small tank in the attic as well as a bigger one.

Certainly have a small and large tank in the attic. 🙂

Sorry, I see you said above that its on speed 1, you could try it on proportional setting (PP) 3 by pressing the setting button for 5 secs the display should then change (to a flashing green LED) and just press the button briefly to iii (flashing). It may be a little weak for your system but just give it a try anyhow, its only a few button presses.

I will certainly try this, John. Thank you. I'll try this over weekend, and report back! Really appreciate your time in helping to troubleshoot.

 

[Ric 2013]

A long shot, but could the rattle be coming from the gate valves where the pipe connects to the pump? Sometimes these can rattle if not fully open. It's general practice to open a valve fully and then back it off a quarter turn or so, but sometimes results in rattle with this kind of valve.

 

[John.g]

Very good, be interesting to see if the reduced head of 1.7M will reduce the noise, I have assumed that you are getting around 13.3 LPM at a 3M head on speed1, if it is around this then you will now get 10.0 LPM which may be sufficient.

 

[SimonG]

Maybe it's not noisy and the other one was overly quiet.

Changed a fill valve on a toilet in a first floor flat. A siamp that had been dodgy for over 3 years. Bloke downstairs playing holy hell because he could hear it fill. He was used to the old siamp just spraying.

 

[Adam_and_the_boiler]

A long shot, but could the rattle be coming from the gate valves where the pipe connects to the pump? Sometimes these can rattle if not fully open. It's general practice to open a valve fully and then back it off a quarter turn or so, but sometimes results in rattle with this kind of valve.

Thank you, Ric. I will keep this in mind; I may, if need be, give the valves a quarter turn to see if it makes a difference!

Maybe it's not noisy and the other one was overly quiet.

Changed a fill valve on a toilet in a first floor flat. A siamp that had been dodgy for over 3 years. Bloke downstairs playing holy hell because he could hear it fill. He was used to the old siamp just spraying.

Quite possibly, Simon! One plumber did say that as our previous pump was of some age, the components were possibly 'looser' and thus flowed quieter to some extent.

Very good, be interesting to see if the reduced head of 1.7M will reduce the noise, I have assumed that you are getting around 13.3 LPM at a 3M head on speed1, if it is around this then you will now get 10.0 LPM which may be sufficient.

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Thank you, John. I have had the pump on the proportional 3 setting for a few days now, while I heat the water. The pump is much quieter, almost can't tell upstairs that it is on, and the water is fine. I haven't tried the heating on yet (but I feel it'll be the end of the week with this weather).

I've googled and understand to some extent, but in very simple terms, what does the proportional settings do, and how do they differ from the actual 1-3 settings? Is this a setting many people use?

Again, thanks for your time.

 

[John.g]

The traditional 3 speed fixed settings which are/were used for 50/60 years worked very well as you get effectively 3 pumps for the price of one, the circulation flow through any system depends on the number of rads, the size of the pipework etc and flowrate is proportional to the (sq.root) pump head or pressure so the pump's three (speed) settings might give 4M,5M & 6M (or even 7M) and if your system only required 4M then running it at 7M takes more energy and cost but it should not really cause a noisy pump, pumps installed on the boiler flow and pumping downwards can be prone to noisier operation for one reason or the other.
Variable speed (smart) pumps were introduced to further increase energy savings, for example my Wilo circ pump only requires well less than half the power of my original fixed speed pump.
Proportional Speed or PP operation further increases energy savings as the pump pressure or head is reduced automatically with reducing flow requirements ie TRVs closing in or Zone valves closing. Some pumps also have different constant pressure (CP) modes which also give bigger savings but are generally used for UFH applications.

UPS's choice of PP setting's unfortunately was and still is to some extent very poor as they were too low, the UPS2 (your one) was/is particularly poor and UPS didn't actually push the advantages of PP control with this model, some arn't even aware that it has PP control.
The UPS 3 was a fairly good step up in PP settings and also includes CP settings, unfortunately your plumber, no doubt in good faith, thought that it was too powerful, probably based on the 3 fixed speed settings, but it was/is more suitable to you than the UPS2 as you can get a slightly higher flowrate on one of its PP settings (or the CP settings) which may have proved to be more suitable for you with all systems opened up, hopefully the UPS2 will do the job for you.

If the UPS3 isn't residing in some installation miles from you and you still have it, I would reinstate it and run it in PP2 mode!!.