Noise from all radiators in new build

jreanor

I have just got the keys to a new build house in the past few weeks. The house is heated by an Air Source Heat Pump (Mitsubishi Ecodan) with underfloor heating downstairs and radiators upstairs. The radiators are fitted with TRVs.

There is a reasonably loud noise coming from all of the radiators when the heating is running. It seems to be the sound of water running through the radiators. I initially thought the radiators just needed to be bled. One of them had a little air but bleeding that that has made no difference.

We have moved in in the last few days and have been closing the TRV completely on the radiator in the bedroom at night so that we can sleep.

A similar noise comes from the shower and taps upstairs. This is less bothersome but may be related.

I have contacted the builder about this and he is following up with Mitsubishi about it. He mentioned that there would always be some noise from water running through the radiators. I will keep on him about it but want to be as informed as I can.

Is there an obvious cause for something like this? Could it be that the pump is running too high or the TRVs are causing the noise?

Is it reasonable for me to expect that the radiators would be silent when the heating is on? I have never noticed constant noise from radiators anywhere I have lived and would expect the same here.

policarp

Might be an airlock.
Just keep bleeding the rads.

mickdw

Is it possibly a pump noise travelling through the structure?
Is it timber frame or block house?

jreanor

policarp wrote: »

Might be an airlock.
Just keep bleeding the rads.

I will try this again. Its worth mentioning that all the radiators are heating up and none of them let any air out when I bleed them.

mickdw wrote: »

Is it possibly a pump noise travelling through the structure?
Is it timber frame or block house?

Its a timber frame house. The noise is definitely coming from the rads, and not the walls. If I close the TRV completely the noise reduces almost completely and is only slightly audible.

John.G

TRVs are a possible source of the noise, they are generally installed on the rad flow (hot) pipe but sometimes (like all of mine) on the return, if installed vertically on the return then they must be of the bi directional type (you will see two arrows on the TRV valve body, some makes of TRVs are apparently far noisier than others.
Also with HP rad heating, the flow rate may be deliberately set very high to get as much heat as possible from the rad by having a very small flow/return temp difference which can lead to noisy TRV operation as well. If you just feel the rads flow/return when fully heated you should get a good feel for the temperature difference. If you can see a external circ pump note its mode and setting. You might also note the TRV make/model.

jreanor

John.G wrote: »

TRVs are a possible source of the noise, they are generally installed on the rad flow (hot) pipe but sometimes (like all of mine) on the return, if installed vertically on the return then they must be of the bi directional type (you will see two arrows on the TRV valve body, some makes of TRVs are apparently far noisier than others.
Also with HP rad heating, the flow rate may be deliberately set very high to get as much heat as possible from the rad by having a very small flow/return temp difference which can lead to noisy TRV operation as well. If you just feel the rads flow/return when fully heated you should get a good feel for the temperature difference. If you can see a external circ pump note its mode and setting. You might also note the TRV make/model.

Thanks for all this info John.

I don't know much about this but from feeling the pipes on one of the radiators, the side with the TRV appears to be marginally hotter than the other side. So it looks like the TRV is on the flow side and there appears to be a very small flow/return temperature difference as you suggested.

The TRV does not have two arrows on it. The brand is Valogin, but I haven't been able to figure out a model number. A photo is attached.

Regarding the pump, I have checked the settings on the indoor unit for the ASHP. The heating pump is set to 5, which is the maximum but also the default according to the manual.

John.G

Is that TRV (or/and all) installed on the flow or return and are all horizontally positioned?.
Can you note the make/model of that circ pump.

Does the UFH have another circ pump positioned on the UFH manifold?
What is the HP flow (and) return temps? and the UFH flow/return temps?

Edit: I see the TRV is positioned on the flow (hot) side so IF it isn't bi directional then positioned wrongly as it should be vertical or horizontal (like all of mine) if positioned on the return.

jreanor

John.G wrote: »

Is that TRV (or/and all) installed on the flow or return and are all horizontally positioned?.
Can you note the make/model of that circ pump.

Does the UFH have another circ pump positioned on the UFH manifold?
What is the HP flow (and) return temps? and the UFH flow/return temps?

Edit: I see the TRV is positioned on the flow (hot) side so IF it isn't bi directional then positioned wrongly as it should be vertical or horizontal (like all of mine) if positioned on the return.

Yes, all of the TRVs are horizontally positioned and seem to be on the flow side from my very unscientific checking of pipe temps, which is the left side.

From what I can tell, and I certainly could be wrong, the circulation pump is within the indoor unit for the heat pump (Mitsubishi Ecodan EHST20D-VM2D). There seems to be just one setting for heating pump speed, settings screen on the unit is attached.

From reading the manual, I think I can check the flow and return temps when heating is running, I will try to get those later when it kicks in.

Is there any way for me to disable/bypass the TRV to determine if it is the cause of the noise?

listermint

Suppose you could take off the trv head and make sure the pin is fully out.

That would leave it entirely open.

POBox19

The new water is a bit fizzy, it should settle down after a bit. Try giving the rads a knock when the system is off to dislodge them before bleeding.
Is the system totally filled with water and up to pressure 1.5 bar? When you bleed the rad is there a flow of water after the air vents?

John.G

jreanor wrote: »

Yes, all of the TRVs are horizontally positioned and seem to be on the flow side from my very unscientific checking of pipe temps, which is the left side.

From what I can tell, and I certainly could be wrong, the circulation pump is within the indoor unit for the heat pump (Mitsubishi Ecodan EHST20D-VM2D). There seems to be just one setting for heating pump speed, settings screen on the unit is attached.

From reading the manual, I think I can check the flow and return temps when heating is running, I will try to get those later when it kicks in.

Is there any way for me to disable/bypass the TRV to determine if it is the cause of the noise?

The tap icon which I presume is hot water is showing speed 5 which I might expect and isn't the "house" icon (heating?) showing speed 5 as well?, you might be able to reduce this based on the flow/return temps later.

Don't know of any way to disable/bypass the TRV's, attached is a photo of a uniflow TRV, I an holding it like it is shown in your attachment and you can see that the flow will be "wrong" ie against the arrow and into the rad, I had (since renewed after 10 years) several uniflow installed in mine but they are/were on the return with the water flowing from the rad and in the direction of the arrow, I am surprised that there isn't any arrow or arrows on yours, if bi directional then you will have another arrow at right angles pointing in the opposite direction.

K.Flyer

policarp wrote: »

Might be an airlock.
Just keep bleeding the rads.

Bleeding radiators does not remove airlocks. It for venting air gathered at the top of the radiator.
Once air has been expelled and water is coming out of the radiator it does not require further bleeding or venting. There are different solutions for any other problems.

K.Flyer

jreanor wrote: »

I will try this again. Its worth mentioning that all the radiators are heating up and none of them let any air out when I bleed them.

Its a timber frame house. The noise is definitely coming from the rads, and not the walls. If I close the TRV completely the noise reduces almost completely and is only slightly audible.

If you have water coming out of the vent screw and the rads are heating then you are wasting your time and effort bleeding them more, it's not going to resolve this issue.
Start by checking all the lock shield valves on the radiators, (the valve at the other end of the radiator) it is quite possible that they are closed down too much and the noise you are hearing is the water being forced through slightly opened valves.
Start with the worse sounding one and open the valve fully (anticlockwise) make a note of how many rotations it takes to get to fully open as you may need to put it back in its original position. If that has a positive response, repeat with all other radiators.
They may need to be balanced later, but for now it's a simple test to try locate the cause of the issue.

jreanor

John.G wrote: »

The tap icon which I presume is hot water is showing speed 5 which I might expect and isn't the "house" icon (heating?) showing speed 5 as well?, you might be able to reduce this based on the flow/return temps later.

Yes, exactly. The house icon indicates the heating pump speed.

John.G wrote: »

Don't know of any way to disable/bypass the TRV's, attached is a photo of a uniflow TRV, I an holding it like it is shown in your attachment and you can see that the flow will be "wrong" ie against the arrow and into the rad, I had (since renewed after 10 years) several uniflow installed in mine but they are/were on the return with the water flowing from the rad and in the direction of the arrow, I am surprised that there isn't any arrow or arrows on yours, if bi directional then you will have another arrow at right angles pointing in the opposite direction.

You are absolutely right, my TRVs do have bi directional arrows, apologies for getting this wrong. A photo is attached.

I took time in updating here as I have been checking the temperature readings and wanted to be sure I was correct. There appears to be only 1 flow temp shared for both UFH and radiators. Attached is the thermistor reading from this morning when the upstairs heating was active. It shows the flow water temperate (THW1) as 30°C and the return water temperature as 29°C (THW2). Attached also is the table from the service manual which defines these abbreviations.

These numbers seem extremely low to me, I would have expected at least mid thirties. The radiators do feel slightly warm when running. Perhaps I have gotten these readings completely wrong.

jreanor

K.Flyer wrote: »

If you have water coming out of the vent screw and the rads are heating then you are wasting your time and effort bleeding them more, it's not going to resolve this issue.
Start by checking all the lock shield valves on the radiators, (the valve at the other end of the radiator) it is quite possible that they are closed down too much and the noise you are hearing is the water being forced through slightly opened valves.
Start with the worse sounding one and open the valve fully (anticlockwise) make a note of how many rotations it takes to get to fully open as you may need to put it back in its original position. If that has a positive response, repeat with all other radiators.
They may need to be balanced later, but for now it's a simple test to try locate the cause of the issue.

Thats very helpful, thanks for that! I'm hesitant to adjust any valves in case the builder blames me for the problem and refuses to fix it. I will follow up with him today to try get a move on it. Balancing sounds like it could be helpful.

Something interesting I have noticed over the past day as I have been looking more closely is that the sound from the radiators persists at all times, even when the radiators are cold and the heat pump control says heating is off. It is much louder when heating is running but is constantly present. The noise is about the same from all radiators. Closing the TRV on any of them reduces the sound to be very quiet but not completely eliminated.

K.Flyer

If shutting the trv greatly reduces the noise but noise persists when heating is supposed to be off, then I would think it may be a combination of issues.
The system when running should be reasonably quiet and when off should be silent.
Given your description of things I would consider checking lockshield valve adjustment / balancing, circulation pump speed settings and if it's still running with system off, location of pump and how it's installed and check underfloor pump for constant running.
Also, call into your neighbours and see if they are having the same issues.

John.G

jreanor wrote: »

Yes, exactly. The house icon indicates the heating pump speed.



You are absolutely right, my TRVs do have bi directional arrows, apologies for getting this wrong. A photo is attached.

I took time in updating here as I have been checking the temperature readings and wanted to be sure I was correct. There appears to be only 1 flow temp shared for both UFH and radiators. Attached is the thermistor reading from this morning when the upstairs heating was active. It shows the flow water temperate (THW1) as 30°C and the return water temperature as 29°C (THW2). Attached also is the table from the service manual which defines these abbreviations.

These numbers seem extremely low to me, I would have expected at least mid thirties. The radiators do feel slightly warm when running. Perhaps I have gotten these readings completely wrong.

You seem to have a setting of 50C for DHW and 30C for UFH & rads, if rad flow/return temps are 30/29c then you are only getting 11.5% of the rated output from your rads, normal rads will generally have a 10C difference (70/60) so it certainly points to 1, rad flow temps far too low and 2, very excessive flowrates, while it is not 10 times the flow rate of normal (impossible with normal circ pumps) it is certainly very high so I would definitely get the installer back.
I would ensure both the TRV & the lockshield valve fully open on just one rad (note the L/shield setting) and see if noise persists, also, if easy to carry out, reduce the HW pump setting from 5 to say 2 and see if noise persists or just reduce the speed setting first and monitor the noise levels.

jreanor

John.G wrote: »

You seem to have a setting of 50C for DHW and 30C for UFH & rads, if rad flow/return temps are 30/29c then you are only getting 11.5% of the rated output from your rads, normal rads will generally have a 10C difference (70/60) so it certainly points to 1, rad flow temps far too low and 2, very excessive flowrates, while it is not 10 times the flow rate of normal (impossible with normal circ pumps) it is certainly very high so I would definitely get the installer back.

A quick correction on this. I just took a new reading it seems more plausible. 35°C for flow and 31°C for return. Perhaps it was just coming on or off when I checked it earlier. Attached reading. I suspect this does not change the two likely causes above.

John.G wrote: »

I would ensure both the TRV & the lockshield valve fully open on just one rad (note the L/shield setting) and see if noise persists, also, if easy to carry out, reduce the HW pump setting from 5 to say 2 and see if noise persists or just reduce the speed setting first and monitor the noise levels.

Just heard back from the builder. I believe they installed the system themselves. He is going to call over to reduce the pump speed, but it doesn't look like he is putting much thought into it to be honest. I will see how that goes and try the other suggestions above. I may have to get someone in who is knowledgeable about these systems to get full to the bottom of this.

K.Flyer wrote: »

If shutting the trv greatly reduces the noise but noise persists when heating is supposed to be off, then I would think it may be a combination of issues.
The system when running should be reasonably quiet and when off should be silent.
Given your description of things I would consider checking lockshield valve adjustment / balancing, circulation pump speed settings and if it's still running with system off, location of pump and how it's installed and check underfloor pump for constant running.
Also, call into your neighbours and see if they are having the same issues.

Adjusting pump and checking lockshield valves seems to be the consensus for first steps anyway. if I have no luck with those or it doesn't resolve fully, I will pester the builder more and possibly look into getting a reputable ASHP installer in for a look. Will certainly ask the neighbours too!

dubrov

It's not normal so just keep pushing the builder to fix

jreanor

Good news! The builder called out today and the noise seems to be completely gone (fingers crossed!).

He turned down the pump from 5 to 3 which reduced the volume of the radiator significantly but not completely and he was ready to be on his way. Pressed a little more, he checked the lockshield valves which were all quite restricted. Once these were opened the noise seems to have been completely eliminated.

Everyone here was right, thanks for all the help! I wonder if the radiators should be balanced now or does it really matter.

P.S. Before the builder called out I read the manual some more to find how to check the flow rate. It was around 20 liters per minute before the change. The manual states it should be between 6 and 12 liters per minute for my setup. It is now running in that range after the pump setting change.

John.G

That's good news.


What model of Ecodan, or output?

What are the flow and return temps now when heating has been on for a while?

How many rads on the system?

mickdw

jreanor wrote: »

Good news! The builder called out today and the noise seems to be completely gone (fingers crossed!).

He turned down the pump from 5 to 3 which reduced the volume of the radiator significantly but not completely and he was ready to be on his way. Pressed a little more, he checked the lockshield valves which were all quite restricted. Once these were opened the noise seems to have been completely eliminated.

Everyone here was right, thanks for all the help! I wonder if the radiators should be balanced now or does it really matter.

P.S. Before the builder called out I read the manual some more to find how to check the flow rate. It was around 20 liters per minute before the change. The manual states it should be between 6 and 12 liters per minute for my setup. It is now running in that range after the pump setting change.

Excellent news.

K.Flyer

jreanor wrote: »

I wonder if the radiators should be balanced now or does it really matter..

It will only matter if some of the radiators are much slower to heat up fully compared to the rest of them.
From cold turn on the system to heat water And radiators. Check the radiators every ten minutes or so until they are up to full temperature, make a note if any are taking much longer or not heating.

jreanor

John.G wrote: »

What model of Ecodan, or output?

The outdoor unit is SUZ-SWM40VA, the indoor unit is EHST20D-VM2D. Attached the page from the manual outlining the correct flow rates.

John.G wrote: »

What are the flow and return temps now when heating has been on for a while?

I will keep an eye on that and update here. The heating doesn't come on much upstairs, which is probably a good thing.

John.G wrote: »

How many rads on the system?

5 rads, 3 bedrooms + 2 bathrooms.

jreanor

jreanor wrote: »

I will keep an eye on that and update here. The heating doesn't come on much upstairs, which is probably a good thing.

Flow and return temps seem to be unchanged. Flow was 35°C and return was 32°C when I checked this morning after it had been running for a while. Seems to be heating fine, the house is cosy.

Also, the rads were quiet overnight.

listermint

jreanor wrote: »

Flow and return temps seem to be unchanged. Flow was 35°C and return was 32°C when I checked this morning after it had been running for a while. Seems to be heating fine, the house is cosy.

Also, the rads were quiet overnight.

To my untrained eye that seems to small of a drop between flow and return i.e not very efficient. Seems like balancing needs to be done. You should be expending more heat out of the radiator than returning similar heat back into the system.

John.G

jreanor wrote: »

Flow and return temps seem to be unchanged. Flow was 35°C and return was 32°C when I checked this morning after it had been running for a while. Seems to be heating fine, the house is cosy.

Also, the rads were quiet overnight.

That's good, that small deltaT will give you the needed max output from that low but (HP) efficient flow temperature, the rad(s) will be producing "only" 18% of their rated output, for example if you have a normally rated 2kw rad it will be emitting 0.36kw or 360 watts so OK as long as the HP is on 24/7.

Also looking at the HP spec, it seems to be 4kw output, is that correct?.

jreanor

John.G wrote: »

That's good, that small deltaT will give you the needed max output from that low but (HP) efficient flow temperature, the rad(s) will be producing "only" 18% of their rated output, for example if you have a normally rated 2kw rad it will be emitting 0.36kw or 360 watts so OK as long as the HP is on 24/7.

Thanks for that insight. The Heat Pump is on 24/7. There is one thermostat upstairs and one downstairs. Heating is set to target room temp mode.

John.G wrote: »

Also looking at the HP spec, it seems to be 4kw output, is that correct?.

Yes, 4kw output is correct.