Radiators Banging

[SUPERS0N1C]

Apologies if this is old ground, I shall try to provide as much information as possible from reading past posts.

I have a Vailant Combi Boiler (not sure which model but can add later if important.)

We have recently turned our central heating back on after a summer where it has not been required.

When the systems turns on any one of 8 radiators in the house begins chattering rather loudly. This can often be stopped by turning the TRV of the radiator in question slightly. Occasionally the noise can be stopped by turning the hot tap on somewhere in the house but this is usually a temporary fix.
More often than not the chattering returns in a different radiator soon (within 15mins) after the quick fix of the initial offending rad.

All of the radiators are fitted with TRVs. (Ishall check tonight if they are bi-directional).

We have only suffered the problem briefly in the pat as we only moved in in May this year and the heating was turned off not long after. The noises have returned with avengence.

From reading past posts I intend to (as mentioed) check the valves tonite. assuming they are fitted to the incorrect end of the radiator would replacing them with bi-dircectional ones be the best initial course of action?

Failing this are there any other fixes that the DIY plumber could attempt before calling in the big guns (with the big call out charges)?

I am unsure again of the make and model of the TRVs.

Nothing significant has been changed in the system since we moved in, I don't know if there was anything major prior to this.

If I have ommitted anything obvious that you require please let me know and i will find out asap.

I need this problem fixing a quickly as possible, my missus is now being a pain in the @rse.

MAny thanks in advance.

 

[Strachan]

Does the boiler look to be a replacement? i.e. the system is older than the boiler. If it does, it sounds like the t.r.v`s aren`t bi-flow and the flow and return from the boiler are the wrong way round. Simple fix, either swap the lockshields and t.r.v`s for eachother on each rad, or swap the t.r.v`s for bi-flow ones.

 

[bster]

does this boiler have an integral bypass?

 

[doitall]

Quite simply as bster nearly said

The system pipework needs a by-pass.

If you have an adjustment on the pump turn it down a notch for now.

Taking the thermostatic heads off will cure the problem and proof my point.

 

[bster]

what do you mean nearly said

i win, thats my goal!!!

(if indeed that was the correct diagnosis)

 

[doitall]

what do you mean nearly said

i win, thats my goal!!!

(if indeed that was the correct diagnosis)

Oh your correct, no questions asked.

Its to do with the system pressure differencial being to high when the valves start to close.

The springs in the valves are set for a certain pressure, if you read the manufacturers information they will give you the range.