Mini microbore

[sierracsierra]

We have a microbore central heating system. The rad in downstairs cloakroom is 6mm dia pipes. The plumbers said they cannot get 6mm fittings so have fitted a new rad (the old one was rusty) and then cut off the 6mm pipes at floor level (as no longer used). The plumbers have put in a new pipe run (approx 15mm dia pipes) one to each end of the new rad. They have also fitted a Thermostatic valve. The problem is that now the pipes make a terrible noise every night, we thinks it is caused by vibration even tho' they are clipped to the wall. Sometimes it stops when we turn the thermo vale up or down, but last night the only way we could stop the noise was to turn the central heating thermostat down in the hall, so the boiler went off.
I guess it may be a pipe size/flow problem, but ANY help would be greatly appreciated. Its a great forum.
I will speak to the plumbers, but I would like to be in a position to know what I am talking about (if you get my drift.
Hope you can help. Regards.

 

[Lagerkhan]

We have a microbore central heating system. The rad in downstairs cloakroom is 6mm dia pipes. The plumbers said they cannot get 6mm fittings so have fitted a new rad (the old one was rusty) and then cut off the 6mm pipes at floor level (as no longer used). The plumbers have put in a new pipe run (approx 15mm dia pipes) one to each end of the new rad. They have also fitted a Thermostatic valve. The problem is that now the pipes make a terrible noise every night, we thinks it is caused by vibration even tho' they are clipped to the wall. Sometimes it stops when we turn the thermo vale up or down, but last night the only way we could stop the noise was to turn the central heating thermostat down in the hall, so the boiler went off.
I guess it may be a pipe size/flow problem, but ANY help would be greatly appreciated. Its a great forum.
I will speak to the plumbers, but I would like to be in a position to know what I am talking about (if you get my drift.
Hope you can help. Regards.

Did it have a thermostatic valve before ?
Does every rad have a thermostatic valve ?
Is it a sealed system ?

 

[TicklyT]

Is the TRV on the right end of the radiator, and the right way round?
some TRVs, even bi-directional ones, can 'chatter' instead of open and close smoothly, particularly if fitted on the return instead of the flow.

 

[sierracsierra]

Thankyou for your responses.
The radiator is new and the pipes to it are new, and no longer microbore (although the rest of the system is). No, the old rad did not have a thermostatic valve, it only had an on/off knob. All other rads in the house have thermostatic valves.
I am not sure what a sealed system is, can you explain please.

I am not sure which is the flow in pipe so cannot tell whether the stat is on the correct end.

Thanks again.

 

[Lagerkhan]

Thankyou for your responses.
The radiator is new and the pipes to it are new, and no longer microbore (although the rest of the system is). No, the old rad did not have a thermostatic valve, it only had an on/off knob. All other rads in the house have thermostatic valves.
I am not sure what a sealed system is, can you explain please.

I am not sure which is the flow in pipe so cannot tell whether the stat is on the correct end.

Thanks again.

That will be the problem then !
You need one rad without a thermo valve otherwise they will switch off when up to temp and the boiler won't like that.
Get rid of the valve and put back what was there

 

[sierracsierra]

Brilliant! Thankyou Lagerkhan, I will give it a try.

 

[stevesey]

In the meantime - turn valve up to max.