Water noise in radiators since installing zones electronic temp controller

Reznik

Greetings,

I have a heating system in my house with radiators in each room and one condensing gas boiler manufactured with Bosch technology sold as a Worcester Greenstar.

Recently i've installed electronic temperature controllers that open and close the radiators valves depending on the temperature setting for each room.

Right after starting using this system, i noticed that the water inside the radiators was making a loud noise, sometimes whistling. I believe this is because the temperature controllers open the radiator valve little enough to warm the room which increase water speed.

Suspecting the boiler was throwing a high flow of water, i've changed the setting for the circulating pump in order to reduce the water noise. There was 4 settings available and after testing a bit i realized the lowest was enough.

This lowest setting reduced the water noise, but not enough because i can still hear it, especially at night watching TV when it can get a bit annoying.

What can i do to reduce this noise? Someone told me about delta P controllers but the condensing boiler is in the kitchen, so the space is limited.
I've read about circulating pumps that can control the pressure but i don't know if it's feasible to change it. The boiler has a circulating pump Grundfos UPM2 15-70 HU1.

Thank you for all the help.

EdTheHeaterMan

Are the valves full open full close? or are the valves variable opening based on room temperature? Describe the electronic valves you are using. Moden number and brand name.

When all the valves are open, does the noise stop?

Does the noise happen always? when only one zone is calling? whenever the pump operates?

This sounds like a flow issue at one or all of the valves

Need more info

Reznik

EdTheHeaterMan said:

Are the valves full open full close? or are the valves variable opening based on room temperature? Describe the electronic valves you are using. Moden number and brand name.

When all the valves are open, does the noise stop?

Does the noise happen always? when only one zone is calling? whenever the pump operates?

This sounds like a flow issue at one or all of the valves

Need more info

The valves open and close gradually. When the temperature in the room gets closer to the set point, they reduce the flow. It's when they make small adjustments to room temperature that the noise is audible.

I believe the noise is worse if only one zone is demanding more heat.

The electronic valve's system i'm using is Caleffi code.
https://www.caleffi.com/international/en-int/catalogue/comfort-control-caleffi-code-wireless-electronic-control-thermostatic-or-convertible-0

Jamie Hall

"The valves open and close gradually. When the temperature in the room gets closer to the set point, they reduce the flow. It's when they make small adjustments to room temperature that the noise is audible."

Then it's hardly surprising. With the exception of certain rather fancy needle type valves, when a valve is nearly closed there is a very high velocity flow between the element and the seat -- and that is going to create a good deal of turbulence (or even cavitation sometimes) and quite possibly vibration of the seat, and that is going to create a noise. That said I'm not at all sure that there's a good solution to the problem. Changing the pressure drop -- and hence the flow velocity -- across the valve will shift the opening range where this occurs, and may also shift the sound out of the audible range. This change in pressure across the valve is probably why the sound seems worse when only one zone is calling, and also why changing the pump setting seemed to help. A true delta P pump might help -- but there is a possibility there that a low enough delta P to make the sound go away will also be too low to get the circulation you need when the valves are open...

Reznik

Jamie Hall said:

"The valves open and close gradually. When the temperature in the room gets closer to the set point, they reduce the flow. It's when they make small adjustments to room temperature that the noise is audible."

Then it's hardly surprising. With the exception of certain rather fancy needle type valves, when a valve is nearly closed there is a very high velocity flow between the element and the seat -- and that is going to create a good deal of turbulence (or even cavitation sometimes) and quite possibly vibration of the seat, and that is going to create a noise. That said I'm not at all sure that there's a good solution to the problem. Changing the pressure drop -- and hence the flow velocity -- across the valve will shift the opening range where this occurs, and may also shift the sound out of the audible range. This change in pressure across the valve is probably why the sound seems worse when only one zone is calling, and also why changing the pump setting seemed to help. A true delta P pump might help -- but there is a possibility there that a low enough delta P to make the sound go away will also be too low to get the circulation you need when the valves are open...

I see. And would it be feasible to replace the current pump with a true delta P pump? Or the only solution is to replace the entire condensing boiler?

Thank you

Jamie Hall

I'm not sure a delta P pump would exactly drop into place -- depends on the the flange dimensions -- but it wouldn't be a hard job to do. Probably save you some electricity, too! No need to blame the boiler.

Reznik

Jamie Hall said:

I'm not sure a delta P pump would exactly drop into place -- depends on the the flange dimensions -- but it wouldn't be a hard job to do. Probably save you some electricity, too! No need to blame the boiler.

I asked because the space is quite limited inside

Jamie Hall

Um... problem. I'd assumed that you had another pump on a secondary loop. Oops. My bad...

EdTheHeaterMan

You can't replace that pump with anything else but the OEM pump.

The boiler you show in the picture is a model normally not found in USA. Is this in UK or EU? As far as Caleffi products are concerned, @hot_rod Bob Rohr is the resident expert on HH.

Maybe he can help now that I tagged him.

Reznik

EdTheHeaterMan said:

You can't replace that pump with anything else but the OEM pump.

The boiler you show in the picture is a model normally not found in USA. Is this in UK or EU? As far as Caleffi products are concerned, @hot_rod Bob Rohr is the resident expert on HH.

Maybe he can help now that I tagged him.

Yes this model is sold in UK but i've discovered that is also sold in EU under a different brand. But in the end it's Bosch technology re-branded.

I tried to search for condensing boilers with the new UPM3 of the Grundfos pump that adapts to pressure but manufacturers don't announce that.

Thank you all for the help.

gennady

You must install flow setters on each radiator and set them to required flow. Also replace your circulator with properly sized deltaP circulator

Reznik

gennady said:

You must install flow setters on each radiator and set them to required flow. Also replace your circulator with properly sized deltaP circulator

But doesn't the electronic valve work as a flow setter?

Jamie Hall

Reznik said:

gennady said:

You must install flow setters on each radiator and set them to required flow. Also replace your circulator with properly sized deltaP circulator

But doesn't the electronic valve work as a flow setter?

Sort of. However, you are probably asking it to run in the low end of its throttling range which, as I noted above, is likely to be noisy. If you use a flow setter to get the full open flow to the level where the radiator would hold a reasonable temperature, and then only asked the electronic valve to reduce that, it would be better. Not going to say it would be great, but likely to be better.

Make a comparison to your car. There are two ways you can control the speed of the car on a level road. You can set the throttle so that the car nicely maintains the speed -- or you can floor the throttle and hold the brake to control the speed.

gennady

You will need to install hydro separator with system deltaP pump. Please make sure boiler accepts system temperature sensor. Modulation of the water temperature to the system will eliminate need of radiator valve to operate on very low rate of opening. Is your boiler operating on outdoor reset?

Reznik

gennady said:

You will need to install hydro separator with system deltaP pump. Please make sure boiler accepts system temperature sensor. Modulation of the water temperature to the system will eliminate need of radiator valve to operate on very low rate of opening. Is your boiler operating on outdoor reset?

The boiler doesn't have a deltaP pump, unfortunately. The electronic valves in the radiators are controlled by a device that turns ON/OFF the boiler according to the need of each room set-points