My radiators have some TRVs installed on the flow pipe, and some on the
return.
Lockshields are on the other end of the rads.

Is this OK?

I believe the TRVs *should* be on the flow pipe.

But *must* they be on the flow?

You can get bi-directional TRVs that can live on the flow or return, so i
guess its not too important.

Last question, one TRV is producing a "shuddering" noise when it stops the
flow.
Is this because it is broken, or on the wrong end of radiator (or possibly
both) and needs replacing?

thanks for any info.

IA

In article ,
IA wrote:
Last question, one TRV is producing a "shuddering" noise when it stops
the flow. Is this because it is broken, or on the wrong end of radiator
(or possibly both) and needs replacing?

Classic symptom of one being used in the 'wrong' direction.

--
*El nino made me do it

Dave Plowman London SW
To e-mail, change noise into sound.

IA wrote:
My radiators have some TRVs installed on the flow pipe, and some on the
return.
Lockshields are on the other end of the rads.

Is this OK?

I believe the TRVs *should* be on the flow pipe.

But *must* they be on the flow?

You can get bi-directional TRVs that can live on the flow or return, so i
guess its not too important.

Last question, one TRV is producing a "shuddering" noise when it stops the
flow.
Is this because it is broken, or on the wrong end of radiator (or possibly
both) and needs replacing?

That is a symptom of a TRV on the return. Most bi-directional TRVs
simply have small holes restricting the flow so the 'shuddering' you
describe is less likely to occur, although one (the Randall(?) RAS-C
Revolver) lets you reverse the flow through the TRV body if this occurs.

In your case your options are (a) move the TRV to the flow end of the
rad (b) turn the TRV body through 90 degrees so it's aligned with the
flow (which means the head will protrude horizontally rather than
standing up vertically) (c) replace with a RAS-C revolver, adjusted
appropriately (d) replace with any other TRV, which may be less likely
to judder.

The message
from John Stumbles contains these words:


(b) turn the TRV body through 90 degrees so it's aligned with the
flow (which means the head will protrude horizontally rather than
standing up vertically)

The closer TRV heads are to the heat the less notice they take of room
temperature in general so a horizontal head on the return gives the best
chance of restricting changes in room temperature when outside
conditions vary.

--
Roger

IA wrote:

I believe the TRVs *should* be on the flow pipe.

But *must* they be on the flow?

You can get bi-directional TRVs that can live on the flow or return, so i
guess its not too important.

Many modern ones claim to work equally well on either end. However I
found that with a TRV on a return (new install, no easy way to know
which was flow and return in advance - 50/50 chance ;-) it whistled as
it closed down, so had to swap it anyway.


--
Cheers,

John.

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Roger wrote:
The message
from John Stumbles contains these words:



(b) turn the TRV body through 90 degrees so it's aligned with the
flow (which means the head will protrude horizontally rather than
standing up vertically)


The closer TRV heads are to the heat the less notice they take of room
temperature in general so a horizontal head on the return gives the best
chance of restricting changes in room temperature when outside
conditions vary.

But this can be a short-lived advantage if there are small children
around who stand on the handily-placed TRV head as though it were a step :-)