Noisy Radiators... we have an ASHP

[sirpatchuk]

I am hoping someone can help as no plumber has been yet.

We have a Samsung 12KW ASHP (no issues with it)

We have UFH downstairs (no issues)

We have radiators upstairs.  When the radiators come on they cause significant noise and I cannot sleep.

We have had people look at it, balancing, draining etc.  Still the noise.  We have 7 radiators upstairs.  The noise is worst in the master bedroom and I think this is the first radiator.  It is hardly anything in the further bedrooms.  

The pipework is all the correct size.  I know very little but it sounds like it must be the water pressure / amount of water trying to get through?

Many thanks.

[JohnMo]

What happens if you just turn off that radiator?

 

Do you get noise elsewhere?

Edited November 16 by JohnMo

[ProDave]

New install?  Boiler swapped for ASHP?  If so was it noisy with a boiler?

[John Carroll]

10 hours ago, sirpatchuk said:

I am hoping someone can help as no plumber has been yet.

We have a Samsung 12KW ASHP (no issues with it)

We have UFH downstairs (no issues)

We have radiators upstairs.  When the radiators come on they cause significant noise and I cannot sleep.

We have had people look at it, balancing, draining etc.  Still the noise.  We have 7 radiators upstairs.  The noise is worst in the master bedroom and I think this is the first radiator.  It is hardly anything in the further bedrooms.  

The pipework is all the correct size.  I know very little but it sounds like it must be the water pressure / amount of water trying to get through?

Many thanks.

 

Have you smart radiator valves controlled by Evohome or such?

Check circ pump settings and post its make/model/mode/settings and flowrate if it displays it.

Check UFH manifold meter settings (throttled etc) and flowrates.

Does one circ pump serve the rads and the UFH?

Where is the expansion vessel located?.

Edited November 17 by John Carroll

[ReedRichards]

I have a few radiators that make some noise.  I think the fundamental problem is that you are trying to achieve a 5 C temperature drop across each radiator and this requires a much higher water flow rate than the 20 C drop that is typically used with boilers. This high flow rate can lead to noise.  You might be able to throttle the radiator valve to reduce the flow rate and so reduce or eliminate the noise but this will reduce the radiator output so you may or may not be able to do this and keep the room warm enough.

[John Carroll]

3 hours ago, ReedRichards said:

I have a few radiators that make some noise.  I think the fundamental problem is that you are trying to achieve a 5 C temperature drop across each radiator and this requires a much higher water flow rate than the 20 C drop that is typically used with boilers. This high flow rate can lead to noise.  You might be able to throttle the radiator valve to reduce the flow rate and so reduce or eliminate the noise but this will reduce the radiator output so you may or may not be able to do this and keep the room warm enough.

 

Well, any flowrate up to ~ 5 LPM with both rad valves fully open, should not be problematic, IMO. Assuming a flowtemp of 42C then the rad output will be 33.4% of a T50 with a dT of 0.95C, if it is running with a dT of 5C then its output is 29.4% of a T50 with a flowrate of  0.84LPM. If it is running with noisy operation at say 7.0LPM then its output is 33.7% of a T50 with a dT of only 0.68C. These numbers are all based on a 1.0kw, T50 rad.

Edited November 17 by John Carroll

[JohnMo]

15 hours ago, sirpatchuk said:

We have UFH downstairs (no issues)

We have radiators upstairs.  When the radiators come on they cause significant noise and I cannot sleep.

Are you switching off the UFH and switching on the radiators?

 

If so that could be the issue. 

 

Do you have a buffer and secondary pump?

 

Or are you running straight off the ASHP.

 

If your UFH is fine, you switch it off, you could be trying to squeeze a lot of flow through a small radiator circuit. Especially if the plumber has balanced the whole system to work as one big circuit.

 

Think we will need much more details about your system and how it is all operated etc. more details the better

[sirpatchuk]

On 16/11/2024 at 22:21, JohnMo said:

What happens if you just turn off that radiator?

 

Do you get noise elsewhere?

Yes, the noise passes onto the next radiator but appears to be less as it goes down

[sirpatchuk]

On 16/11/2024 at 22:34, ProDave said:

New install?  Boiler swapped for ASHP?  If so was it noisy with a boiler?

We had an oil system before and all new pipework put in.  Pipework correct size.

[John Carroll]

2 hours ago, sirpatchuk said:

We had an oil system before and all new pipework put in.  Pipework correct size.

In another thread you also had a Grant ASHP 17 KW, did you have noise while this was installed or is it at another location?

[sirpatchuk]

12 hours ago, John Carroll said:

In another thread you also had a Grant ASHP 17 KW, did you have noise while this was installed or is it at another location?

 

Hi.  Yes - the other thread was the problems with my UFH.  We had the noise then with the upstairs radiators too.

After a lot of pain we had all the UFH heating ripped out as it was simply never going to work.  We now have an overlay system UFH downstairs which works, and they swapped the Grant 17KW for a Samsung 12KW.  The Grant ASHP worked but they said it was oversized.

When the new installers did the UFH work I asked them to look at the radiators too.  They did but said all the pipework looked fine..

Edited November 19 by sirpatchuk

[sirpatchuk]

On 17/11/2024 at 08:25, John Carroll said:

 

Have you smart radiator valves controlled by Evohome or such?

Check circ pump settings and post its make/model/mode/settings and flowrate if it displays it.

Check UFH manifold meter settings (throttled etc) and flowrates.

Does one circ pump serve the rads and the UFH?

Where is the expansion vessel located?.

 

Thanks for the reply.  Sorry, but a lot of this I don't understand so I apologise if I give the wrong terminology or ask a silly question.

 

I attach pictures and can provide more.

 

We have Evohome with four zones;
Downstairs three zones for the UFH.
Upstairs one zone which controls all the upstairs radiators which all have TRVs.
It is difficult to tell but I would say that when it is only upstairs calling for heat the noise is worse yes.

 

I understand that there is one pump for the UFH and one pump for the radiators - both Grundfos.

 

 

Edited November 19 by sirpatchuk

[JohnMo]

You mentioned above when the bedroom radiator come on. Do you switch sections of the heating on and off? Do you have the same noise with everything on?

[sirpatchuk]

Although we have four zones (three downstairs and one upstairs), they are all set to the same temperature(s) and for the same times.  We are on Octopus ASHP tariff so at the cheap times we up the temperature.  So generally at 0400 the house requires heat.  It may be the case that only upstairs requires it, it is dependent on temperatures.  However, I have tested it but forcing only upstairs to come on.

[John Carroll]

1 hour ago, sirpatchuk said:

 

Thanks for the reply.  Sorry, but a lot of this I don't understand so I apologise if I give the wrong terminology or ask a silly question.

 

I attach pictures and can provide more.

 

We have Evohome with four zones;
Downstairs three zones for the UFH.
Upstairs one zone which controls all the upstairs radiators which all have TRVs.
It is difficult to tell but I would say that when it is only upstairs calling for heat the noise is worse yes.

 

I understand that there is one pump for the UFH and one pump for the radiators - both Grundfos.

 

 

 

Can you identify which pump is serving the CH (rads only)  by just requesing rads only on and then take a photo of the front of the pump showing its LEDs, which should show what head the pump is producing.

 

 

[sirpatchuk]

On 19/11/2024 at 10:58, John Carroll said:

 

Can you identify which pump is serving the CH (rads only)  by just requesing rads only on and then take a photo of the front of the pump showing its LEDs, which should show what head the pump is producing.

 

 

ok… turns out only one pump feeds both the ufh and radiators..

just had this email from the installer;

 

The system has two pumps, one of the pumps feeds the hot water to the low-loss or the hot water tank. The second pump is after the low loss which feeds both the radiators and the UFH. This pump feeding the UFH and the radiators is on its highest setting 

Edited November 20 by sirpatchuk

[John Carroll]

 

Unless this pump has a external (PWM) signal then it will only run at the highest speed,  a 7M head.

This will more than likely cause noisy operation IMO especially when coupled with  Evohome control which continually throttles the motorized rad valves, don't know what the cure for this is.

[sirpatchuk]

We are using normal trvs, not the digital evo home ones.

can it be setup so there is a pump for the ufh and a pump for the upstairs radiators? Would that change anything?

[marshian]

1 hour ago, sirpatchuk said:

We are using normal trvs, not the digital evo home ones.

can it be setup so there is a pump for the ufh and a pump for the upstairs radiators? Would that change anything?

 

Why not try turning the pump speed down?

 

I would be surprised in the system needs a pump running flat out unless it's a really big system with a lot of rads and UFH

 

I've got 13 rads no UFH and I have a smaller pump running on min speed (out of 3) - I can run it faster but the temp drop on each rad gets narrower and system noise increases as TRV's start to restrict flows

 

In fact I'd actually try the slowest speed and work up from there if the house room temps started to nose dive (it's currently a good environment to do this exercise) I'd gradually increase pump speeds until control was there

[John Carroll]

It states above, "Without PWM signal, the pump runs at maximum speed" so if there isn't another cable plugged into the pump PWM socket and it looks like there isnt, then that pump will be running at a 7M head so  can't be set to one of its other heads down to 4 or 5M?. These UPM type pumps seem popular with UFH systems, wonder why, as all the normal type can run in all the different modes/settings. most don't have this PWM socket but its  very rarely needed.

[marshian]

10 hours ago, John Carroll said:

It states above, "Without PWM signal, the pump runs at maximum speed" so if there isn't another cable plugged into the pump PWM socket and it looks like there isnt, then that pump will be running at a 7M head so  can't be set to one of its other heads down to 4 or 5M?. These UPM type pumps seem popular with UFH systems, wonder why, as all the normal type can run in all the different modes/settings. most don't have this PWM socket but its  very rarely needed.

 

I don't read that the same way - sorry

 

I read that as without PWM the pump can be run at one of 4 speeds

 

[John Carroll]

That makes sense, I think those settings are 4M,5M,6M&7M, so try the 4 or 5m curve.

[marshian]

54 minutes ago, John Carroll said:

That makes sense, I think those settings are 4M,5M,6M&7M, so try the 4 or 5m curve.

 

I'd be starting at the slowest speed possible and seeing how the system responded

 

If the rad circuit has been balanced using the lockshields for a pump set to max you might have to allow a little bit more flow thro the rads but it may not be necessary - I can run my pump on 1 or 2 with no re-balancing required - only difference is the difference between flow and return on each rad drops with an increase in pump speed.

[John Carroll]

Looking at the OAP's pump it seems to have just 3 speeds so should be just a case of pressing the setting button (arrow) and try speed I, first check and see if its running at setting III.