I can hear the flow of water after balancing

[bhm1712]

i balanced my rads using the method described on this site, and using an infra red aim and shoot thermometer.
All of the rads now get red hot like i wanted, but i can now hear the water flowing through the rads quite loud, not a humming, just water hiss associated with flow. the pump is on speed 2.

if i open all the LSV by 1 turn the noise quitens down but the downstairs rads start to be colder again. is there anything i can do to make it quiet? or will i have to deal with it if the system is balanced ok?

 

[bhm1712]

for info purposes, the pipe size is 15mm upstairs, branching off a 22mm ring main. Downstairs its microbore.

there is no air in the system, the pump is a wilo gold.

 

[Steve69the69Gas]

Try pump on speed 1.
Could be a little air in there tho.

 

[bhm1712]

no its not air, the system is fully bled, i cant really explain what i mean but i know what air sounds like in a system, and this isnt it if you understand me? when i drained down the system and there was still air in it made more trickling noises etc. im sure this is purely noise resulting from the restriction of flow by the LSV

for example, if you flush the toilet and listen to it filling back up, its that kind of noise, just water flowing..

 

[D_Hailsham]

if I open all the LSV by 1 turn the noise quitens down but the downstairs rads start to be colder again.

Which balancing instructions did you follow?

One turn is a lot! The LS valve will be almost fully open then. Try an eighth of a turn at a time.

Presumably the downstairs micro-bore is also fed from the same 22mm ring main as upstairs. The problem is that the micro-bore pipes present a much higher flow resistance than 15mm , so the LS valves on the 15mm pipes have to be closed right down if the microbore rads are to get a look in. (I am assuming, from what you say, that the 15mm rads are earlier in the circuit.) Ideally the 15mm rads should be on a separate branch from the micro-bore, it would then be possible to have a balancing valve in the 15mm branch so the LS valves on each rad would not have to be closed so much.

 

[bhm1712]

unfortunately i think the microbore is fed from the same 22mm ringmain upstairs and the plans i do have show no balancing valve or anything like that.

i followed the instructions which to cut a long stroy short said i need to adjust until i get a 11 degree drop over the flow and return pipes.

the 15mm is first on the system yes

 

[D_Hailsham]

unfortunately i think the microbore is fed from the same 22mm ringmain upstairs and the plans i do have show no balancing valve or anything like that.

I didn't expect you to have a balancing valve.

i followed the instructions which to cut a long stroy short said i need to adjust until i get a 11 degree drop over the flow and return pipes.

Is this same installation that you converted to C Plan or another one?

Do you have TRVs on any rads?

If so, did you balance with the TRV heads removed?

This is what you should really have:
[code:1]

(downstairs rads) ---------------------(balance valve)------(upstairs rads)
|
|
|
PUMP
|
|[/code:1]

 

[bhm1712]

yes it is the system i changed to c plan, however this attempt to balance the system i did before the conversion and the water flow noise was there then as well, i never really thought much of it until a friend visited and commented how loud it was! now i can hear it all the time!

 

[bhm1712]

right, i turned the LSV down to 1/8 on all the upstairs rads and the noise is gone, however 2 of the rads do not get very hot now, so i will borrow the thermometer again and try to balance them properly again with the 1/8 figure in mind!

 

[D_Hailsham]

right, I turned the LSV down to 1/8 on all the upstairs rads and the noise is gone, however 2 of the rads do not get very hot now, so i will borrow the thermometer again and try to balance them properly again with the 1/8 figure in mind!

I was not saying that you should turn the LSV down to 1/8 but that any adjustments should be no more than 1/8 of a turn at a time. When you opened the LSVs a whole turn, you would have completely upset the balance.

Try this Balancing Procedure