Deeply annoying clicking sound when heat is on

usually heaters make a racket from pipes/metal expanding?

is there a thermostat on the radiator or any zone valves in the system?

ArtSmart wrote: »

no, they are metal brackets and metal spacer.



there is a 'full flow' valve on one side on most of the rads, but not on all them. the other side is an off/on knob.

If the plastic spacers are not fitted to the radiator brackets you will suffer from expansion noise, that's what they are supplied to prevent. :rolleyes:

ArtSmart asks:

1.

Originally Posted by heinbloed
Propably an expansion/contraction problem, as a Billy Bunting said.
Try to find the source. If it can be acessed try to sprinkle talcum powder (chemist) onto the source. This would work like oiling, but don't use oil!

Firstly thanks for the detailed reply. but i dont really understand most of it. so...
do you mean onto the pipes leading to the rad?

I mean to put talkum powder onto the points where temperaturedifferences are apearing, sudden changes of temperature. For example at the radiator holding brackets, between the hot radiator and the cold bracket.
Or onto the pipe surface where it is in contact with a cold surface like a floor board.

2.

If the source(s) can't be found the only other remedy is to keep the flow/return temperature at a constant level.

how do i do that?

The ( modern) boiler has various parameters to be set manually. One of these is the difference between flow and return, the temperature difference between the outgoing hot water and the returning cold water.
The usual temperature difference between the two is 20 degrees. But ask your plumber/heating engineer, read the boiler manual as well.
This setting means that for example the boiler heats up to 70 degrees Celsius (flow, boiler outlet) and the return temperature would be only 50 degrees Celsius, after giving off parts it's thermal energy to the radiator.

So the 70 degrees Celsius will heat-up the pipe which will expand and rub on the cold bracket, the floor board ect.. The warmer an object gets the more it expands. Reduce the flow temperature and you'll reduce the expansion of the pipe/radiator as well. And this will reduce the physical impact of the expansion, the noise caused by rubbing two objects.

3.

If doing so using the boiler thermostat/control settings then this would be costly, consuming enormous amount of fuel.

I simply dont understand this sentence. can you break it down for an idiot (me)

Most boilers are oversized themself, not chosen for a central heating systems which is balanced.
With such an unsuitable source of thermal energy (the boiler!) there is always a pendular boiler operating seen: the boiler fires up for a few minutes, senses overheating at the return pipe, stops firing, cools down and then fires-up again. And so on. A common problem when incompetent specifiers have asked the installer for an unsuitable boiler. They ask for it because they're to stupid and/or they want to get rid of a batch of cheap boilers, be they suitable or not...

Better it would be to reduce the output of the boiler(setting it correctly or choosing a smaller, modulating boiler), referring to your question:

The first thing obvious might be to try to reduce the flow temperature to decrease the running time of the boiler.

em, say what? do you mean have the heating on less?

Not having the heating system less on but the reducing the amount of heat which it produces. Meaning to get the room warm not in ten minutes but in 30 minutes is cheaper. This is achieved by reducing the flow temperature, the radiator won't get as hot as before but will be less hot.
The thermal supply time will increase, the boiler running more but putting out less.
Or to put it into a picture: Instead of running to fetch the bus one can walk. It takes longer to get to the stop and saves energy (here:food).
One wouldn't overheat (waste energy) and one wouldn't pant (noise reduction). It takes a bit longer but saves plenty of energy when starting earlier.

What leads to the last question:

This will certainly help but might not be enough, see above.
The next thing -if above remedies fail- is to look for a modulating boiler with a lower output. This would run continously. And no more expansion or contraction whilest running.

em...

The boiler might be oversized, it might be set wrongly, the entire heating system might be wrongly dimensioned.
If the DIY methods don't help the problem (reducing the systems peak temperature, talkum powder at rubbing parts, plastic spacers between brackets and radiator or between pipes and pipe brackets) all you can do is to get a plumber/heating engineer in who will have a look at the overall system.
His recommendation might be (it would be my recommendation anyhow) to reduce the peak temperature created by the boiler and let it run continously. This would work only with a boiler which is suitable to run on a low output.
There are boilers nowadays available which start with a minimum output of 1.8 kW. Meaning they'll supply 1 or 2 radiators continously without switching on or off.
The larger the min. output of a boiler is the more it will pendulate, it will turn on and off.
The smaller the output is the less likely temperature fluctuations will apear.
And therefore no expanding and contracting whilest operating, no squeaking noises.

To boil it down :

The squeaking is caused by an unsuitable heating system.

It can be adjusted to get less or no squeaking at all.

The boiler might have to be replaced with a smaller one.



PS
My excuses for the messy text apearance