Elephant in the Room or is it Just our Dual Fuel Towel Radiator Making Loads of Noise? All aspects of plumbing questions and answers, help, tips and information

[supersadie]

Hi
I have a combi boiler with radiators and a number of 'plumbed in' towel rails, one of which is dual fuel.
Every day, several times a day, we have a loud trumpeting sound (see title!) from this towel rail and sometimes from the ordinary non fuel one too. I have bled them, but it makes no difference. It seems to come on spasmodically, but it might coincide with the thermostat deciding the temp is too low and the boiler firing up again. The only thing that stops it is turning the TRV. Both noisy rails are upstairs although there is a quiet one that won't bleed at all although I've tried - no water, no air.
I have asked two plumbers and got three different answers so hoping a clever soul on here could help. Boiler about seven years old, regularly serviced.
Many many thanks.

[stoneyboy]

Hi supersadie,
Deal with the obvious one first - when the radiator makes the noise take a stick put it to your ear and hold it on the TRV, you'll soon know if the valve is the problem. The jumper in the TRV could be loose and vibrating with the water or the TRVs have been fitted the wrong way round - some are still flow sensitive, replacement is the only option.
Regards, stoneyboy