noise when trv at maximum

[wrathkeg]

Hi all,

Maybe there is an obvious answer to this. But I don't know what it is!

I have a newish Vaillant combi boiler, and TRVs on the radiators. On one of the radiators there is the noise of rushing water, but only when the TRV is turned up between 3 and 5. The noise isn't terrible, but enough to wake people up when the heating comes on in the night. Is this normal? I suppose one answer is to keep the TRV lower, but that doesn't seem quite right to me. I have bled the radiators twice. A bit of air came out of the radiator making the noise, but it didn't fix the problem.

Thanks in advance,

wrathkeg

 

[denso13]

Close the lockshield valve (other side) and open it half a turn as it might slow down the flow through the radiator. Note how far the valve was originally open, number of turns to close it, incase it causes any problems with other radiators.

 

[wrathkeg]

thanks for that. i thought of that this morning, and gave it a try, but it didn't make any difference.
wrathkeg

 

[D_Hailsham]

The noise isn't terrible, but enough to wake people up when the heating comes on in the night.

Does you house cool down so quickly that you need the heating on overnight?

What night-time temperature do you have the stat set to?

The noise is caused by too fast a flow through the rad. This suggests that the system has not been properly balanced.

How big is your house?
Which Vaillant boiler do you have?

 

[denso13]

Is it a recent thing or has it always done it? Are the other rads ok on the high setting? Is the TRV on the correct way round - there should be arrow on the body showing the flow direction but it may be bi-directional. Take the head off completely - does it still make a noise?

 

[wrathkeg]

well, it would be fine for me not to have it on overnight but the wife complains.... we have the thermostat set to 19.5 for overnight. Also, I don't really know when it started it. It was --- surprise surprise --- the wife who pointed out the noise. I hadn't noticed it myself, but now she has mentioned it I have to admit: it is pretty loud.

Maybe the answer to all this is get a new wife?

Anyway, the boiler is an Ecotec 831 plus, and the house is pretty small (3 bedroom 1930s semi). It is possible balancing is the issue. While I am confident the plumber would have done this when installed, since then we have had work done to the water main, so the water flow is much higher than when installed which I suppose might have changed things?

I'll see about trying to balance it, though that might have to wait until I am off work for Christmas.

Thanks all,

wrathkeg

 

[Agile]

See the FAQ for how to balance the rads.

Even if bidirectional they are better at the flow end.

Tony

 

[Agile]

See the FAQ for how to balance the rads.

Even if bidirectional they are better at the flow end.

Tony

 

[D_Hailsham]

we have the thermostat set to 19.5 for overnight.

Drop it a bit at a time and see if she notices.

How well is your house insulated? There are plenty of deals available for cheap insulation. See Energy Savings Trust Grant Search

Anyway, the boiler is an Ecotec 831 plus, and the house is pretty small (3 bedroom 1930s semi).

The boiler is almost certainly oversized for your heating requirement. The full output will only be required for providing hot water.

Use the Whole House Boiler Size Calculator to find out your heating requirement. Set the Domestic Hot Water Allowance to 0 as you have a combi boiler.

The boiler heating output should be set to slightly above the result. (Parameter d.0).

Did the installer adjust the built in automatic bypass?

What is the pump control setting (Parameter d.19)?

 

[dannyboy85]

i have the exact same problem on one of my radiators, with a trv.

the only way Ive found to get it to stop, is turning down the heating pump.
Im not sure if this is the right thing to do...
but its not recommended to for all systems, so check first!

 

[SShar]

Sounds like a system balance problem to me, i'd get the installer back. Best of luck

 

[dannyboy85]

mine was a balancing thing.

Ive cured the problem myself.

 

[wrathkeg]

well, I seemed to have solved it. turned all the TRVs to max, closed all the lockshield valves, then opened all of them half a turn. The radiators seem to be heating up nicely, and no noise.

now i need to find something useful to do with the infrared thermometer I just spent 20 quid on....

thanks for all the help

wrathkeg

 

[dannyboy85]

yeah

what I didnt realise that apparently... when it comes to lockshield valves, only the first 1 and a half turn matters.

after that its on full flow anyway.

but yeah, like mine... I imagine the problem was too fast flow = glugging sound. so turning down the lockshield valve helped.

I know its not professionally balancing the system... but if you find one or two radiators aren't getting warm enough, quickly enough, you can always open it up a bit more.

The thermostat valve will still work as it did before, and cut off the water supply when it gets to the correct temperature....... hopefully, minus the glugging noise.