Intermittent noises from CH system

4 Dec 2004
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United Kingdom
Over the last year my CH system has become very noisy on an intermittent basis. We get loud humming and banging noises from some of the radiators which can only be stopped by turning the relevant thermostatic valve up full. Any ideas how to cure?
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Do all the radiators have thermo valves? If yes then
If the noise happens principaly when the house is nice and warm, it could be the pump ahs to fight hard against all the closed valves to get water to circulate any carry heat away from the boiler.

To cure this you can replace the thermo valve on one of the rads with a wheel head valve or just leave the thermo set to max.

The best solution would be an automatic bypass valve. Some modern boilers have them built in. Check yours does not by refering to the user instructions.
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All rads are properly bled.

To Brummylad:
Yes, thanks for the suggestion. I was beginning to come to a similar conclusion. Do you have any good ideas as to how to change a radiator valve without fully draining down the system (as it has just been poweflushed and refilled)? Do you have any experience of using freezer sprays to provide an ice-block in the feeder pipe?

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