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 17 hours ago 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 7 hours ago 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 2 hours ago 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