Grundfos ups3 making noise

[BlueLoo]

Constant pressure doesn't work for plumbing with variable flow.
Basic fluid mechanics.

Constant pressure means that flow reduces as area (valves close) reduce. It can't cope with system loss and differential.

This is why it's used primarily for ufh.

PP whilst not perfect is actually designed for head loss found in typical CE systems.

It's not perfect but nothing is.

Use PP.
Or CS.

How to choose the correct speed control for heating systems | Xylem UK

www.xylem.com

 

[noddy997]

Constant pressure doesn't work for plumbing with variable flow.
Basic fluid mechanics.

Constant pressure means that flow reduces as area (valves close) reduce. It can't cope with system loss and differential.

This is why it's used primarily for ufh.

PP whilst not perfect is actually designed for head loss found in typical CE systems.

It's not perfect but nothing is.

Use PP.
Or CS.

How to choose the correct speed control for heating systems | Xylem UK

www.xylem.com

Unfortunately my problem still persists with the new pump. 3 port valve is clicking and sending voltage to pump but pump not working. This is a new pump and same problem with old pump

 

[Johntheo5]

The low settings don't push the heat around I've put it on constant pressure 2 yes it's noisy but not as before

IF CP2 is doing the job but still a bit noisy then try it on CS2 at 4.2M, a slightly lower head than CP2 at 4.5M.

 

[noddy997]

IF CP2 is doing the job but still a bit noisy then try it on CS2 at 4.2M, a slightly lower head than CP2 at 4.5M.

View attachment 324270

How do you alter the head?

 

[BlueLoo]

IF CP2 is doing the job but still a bit noisy then try it on CS2 at 4.2M, a slightly lower head than CP2 at 4.5M.

View attachment 324270

Give it up eh?

That's not how pump curves work.

 

[BlueLoo]

How do you alter the head?

Read the curves.

CS = increase flowrate.
CP = you can't
PP = decrease flowrate.

Flowrate is more a consequence than a variable.

You just get a certain flowrate at a certain head.

If you throttle the flow, head can vary as shown.

 

[noddy997]

It has decided to become very noisy at constant speed 2.

The boiler was set to 70c yesterday as ut was cold.

The hot water is surprisingly still at hot ar this hour despite it went off at 7pm.

Constant speed 1 is too low to push heat around, and if hot water is on too then barely the HW and CH get hot

 

[Johntheo5]

Just to be sure, to be sure, can you re confirm that the arrow on the pump body is pointing to the left, ie, towards the mid position valve.
You have 11 rads, 9 of which are Type22 so probably require ~ or > a 3.5M head, you say CP2 was OK? but a bit noisy, this runs at 4.5M. you might try constant curve 2, which at 4.2M should be less noisy and still satisfy the circ required.

You have a open vented system, can you post or describe the vent and cold feed arrangement, you may see them to the right of the pump, you would generally have, closest to the pump, the cold feed, then within 150mm of this, the vent which rises up and over the small F&E cistern in the attic, obviously check that the F&E cistern is ~ a "1/4" full of water.

 

[MNW67]

Constant pressure doesn't work for plumbing with variable flow.
Basic fluid mechanics.

Constant pressure means that flow reduces as area (valves close) reduce. It can't cope with system loss and differential.

This is why it's used primarily for ufh.

PP whilst not perfect is actually designed for head loss found in typical CE systems.

It's not perfect but nothing is.

Use PP.
Or CS.

I've always struggled a lot with understanding this, so that explanation and the article are really helpful. One thing which still niggles is Worcester Bosch approach. If I am understanding their instructions, they use Constant Pressure and the default is 250 mbar. Does that make any sense?

 

[Johntheo5]

The above characteristic map is just telling/showing you that the pump is a 7.2M pump and, see below, when set to a 4M head will maintain this (by speed modulation) until the pump is running at maximum power and similar with all the other CP settings, the lower the head, the greater the flowrate as the power required is less so more circulation until max power.

Radiator systems can and do run perfectly well with a constant pressure, while CC constant curve (fixed speed) and PP proportional pressure are the recommended modes. Ironically, the UP3 does not have any CC modes, CC3 runs at constant pressure (which is NOT fixed speed mode) until it hits maximum power at 60W, the head will then just fall off if the system requires a greater flowrate at a lower head. The other 2 CC curves are hybrid at best, they run at CP for part of the demand.
Also Grundfos PP modes are generally far too low, I have a fairly modest 10 rad system with a 6M Wilo Yonos Pico circ pump, my requirement, with all TRVs open is ~ 15LPM @ a 3.2M head, the CP&PP heads on this pump can be changed incrementally in 0.1M steps to give almost any required flow&head, (it also has the 3 traditional "CC speeds) the system will run perfectly in CP mode @ 3.2M with no noise even with the TRVs throttling right down, if I run it on CC2 which is 3.8M then again runs fine but one TRV does "sing" a little when throttled right down.
I run it at a PP head of 4.0M which gives me the required 3.2M required to circulat at 15LPM and will then reduce the head (proportional control) as the TRVs throttle in.
Even though the UPS3 is a very powerful pump if I had this installed and set it to its highest PP2 setting of 3.8M it would only give a head of 2.3M and 12.2LPM.

Most A rated pumps dont have true CC (fixed speed) curves, my one, below is fairly typical.

 

[noddy997]

Just to be sure, to be sure, can you re confirm that the arrow on the pump body is pointing to the left, ie, towards the mid position valve.
You have 11 rads, 9 of which are Type22 so probably require ~ or > a 3.5M head, you say CP2 was OK? but a bit noisy, this runs at 4.5M. you might try constant curve 2, which at 4.2M should be less noisy and still satisfy the circ required.

You have a open vented system, can you post or describe the vent and cold feed arrangement, you may see them to the right of the pump, you would generally have, closest to the pump, the cold feed, then within 150mm of this, the vent which rises up and over the small F&E cistern in the attic, obviously check that the F&E cistern is ~ a "1/4" full of water.

View attachment 328702


View attachment 328701

I had it on CC2 for over a month it was fine. CC3 was too loud and CC1 wasn't doing the job ie rads were lukewarm at the most and HW wasn't getting hot.

But since last night it has got very noisy at CC2.

The arrow is correctly pointing towards the valve. There is a vent in the loft which I will open to see if any air in it.

I did close the gate valve on my last visit to the loft when I changed the wiring centre. Shall I open it slightly?

I will have to inspect the cistern.

 

[fixitflav]

I had it on CC2 for over a month it was fine. CC3 was too loud and CC1 wasn't doing the job ie rads were lukewarm at the most and HW wasn't getting hot.

But since last night it has got very noisy at CC2.

The arrow is correctly pointing towards the valve. There is a vent in the loft which I will open to see if any air in it.

I did close the gate valve on my last visit to the loft when I changed the wiring centre. Shall I open it slightly?

I will have to inspect the cistern.

Was it OK with the old type grundfos ups15 50? Why was the pump changed?

 

[noddy997]

Was it OK with the old type grundfos ups15 50? Why was the pump changed?

The old red ones? Not had that in years.

Systems had a power flush and water is crystal clear

 

[fixitflav]

The old red ones? Not had that in years.

Systems had a power flush and water is crystal clear

I asked because in #7 you said "Originally I had the old type grundfos ups15 50 I believe the ones with 3 fixed speed settings and that used to be on the highest setting." Have you only had the problem since the UPS3 was installed?
I have a UPS2, looks similar to the previous red UPS15-50.

 

[noddy997]

I asked because in #7 you said "Originally I had the old type grundfos ups15 50 I believe the ones with 3 fixed speed settings and that used to be on the highest setting." Have you only had the problem since the UPS3 was installed?
I have a UPS2, looks similar to the previous red UPS15-50.

I had that years ago, it was on the highest setting yes.

The ups3 have always been problematic. Which thing hasn't been when there's a microchip or circuit board in it?