Banging pipes woe

[spoony1977]

Hi people
I moved house recently and whenever i switch the central heating on (combi boiler) There is an almighty banging in the pipes upstairs.
I have bled the upstairs radiators but that didnt clear it up so im seriously contemplating ripping the carpet and floorboards up as the noise is enough to hear over the TV and also stop us sleeping.
The only thing that worries me is finding the noise as no matter where u stand upstairs it seems thats where the noise originates

Any advice?
The boiler is a vokera compact he

Kind regards

 

[seco services]

have you checked any trv's on the rads. they can cause banging

 

[spoony1977]

Thanks for the reply but im afraid im a complete novice so if you could explain what a trv is and how and what im checking it for that would be great.

 

[seco services]

this is a trv

on the end of your rad.
open the trv fully to the highest number, do they still bang.

 

[spoony1977]

Right im guessing they are thermostatic radiator valves from reading up.
What do i need to do to them to check if there causing said banging?

 

[spoony1977]

Ive done that in the room where the noise is loudest (the front bedroom) and the problem still persisits. There is also a towel radiator in an ensuite in this room and i have tried both radiator and towel radiator fully hot and totally off and the banging is the same.
Should i try opening the TRVs in all the rads upstairs?

 

[seco services]

can do it may not be them. but its a simple check.

 

[spoony1977]

Yep same banging even with all upstairs trvs open
How can i properly locate the origin of the bang?

 

[seco services]

have you tried holding any visible pipework

 

[spoony1977]

The only visible pipework upstairs is the little bits under the trvs before they go under the floor these seem too solid to detect any movement?

 

[gigz]

You've tried them open, now try them closed (all but the towel rail or any that don't have trv's) If this works open one at a time to narrow it down. Some trv's are bi-directional some not. P.S. does the towel rail have trv's fitted ? if so close this as well.

 

[spoony1977]

I will try with them all closed.
The towel rails and a couple of radiators downstairs dont have TRV's but do have closeable valves with a + and a - symbol on them but from playing about twith them i dont think these are a temperature gauge as they just seem to be on or off.
Can switching all my upstairs radiators off not mess with the balnce of the central heating?

 

[gigz]

Not if you only close one side (i.e. trv)

 

[spoony77]

Not if you only close one side (i.e. trv)

On rads with no trv's how do you know which side should be closed and which side open? - and does this include towel heaters?

 

[seco services]

shut the flow side. the one that gets hot first.
if not shut any side but count how many turns so you can put it back.