Faulty TRV head or fault plumber?

[Woby Tide]

I've searched around a bit but most queries regarding broken TRV's are
in reverse where the radiator is cold due to the pin being stuck. Does
it also happen in reverse? We have 3 or 4 radiators fitted with TRV's
that remain permanently hot regardless of where the TRV is set too. The
remaining radiators fitted with TRV's all work fine and can shut off
accordingly.

I guess removing all the heads to see if the pin is stuck permanently
on is first port of call but is it likely that 3 or 4 would fail with
exactly the same issue at the same time or is the whole unit likely to
need replacing as valve (or whatever restricts the flow) is broken?

(At an outside guess could the TRV's have been installed on wrong side
of radiator, but surely that would be exceptionally unlikely? They were
installed some tme in last 10 years and I think it's likely to have
been done by plumber as whole system was replaced during an extension
build so likely to have been a 'proper' plumber rather than DIY)

 

[TMC]

I've searched around a bit but most queries regarding broken TRV's are
in reverse where the radiator is cold due to the pin being stuck. Does
it also happen in reverse? We have 3 or 4 radiators fitted with TRV's
that remain permanently hot regardless of where the TRV is set too. The
remaining radiators fitted with TRV's all work fine and can shut off
accordingly.

I guess removing all the heads to see if the pin is stuck permanently
on is first port of call but is it likely that 3 or 4 would fail with
exactly the same issue at the same time or is the whole unit likely to
need replacing as valve (or whatever restricts the flow) is broken?

(At an outside guess could the TRV's have been installed on wrong side
of radiator, but surely that would be exceptionally unlikely? They were
installed some tme in last 10 years and I think it's likely to have
been done by plumber as whole system was replaced during an extension
build so likely to have been a 'proper' plumber rather than DIY)

Fitting wrong end would not prevent the valve closing.

2 possibilities

1) plunger inside has jammed open..... remove head and test body by pushing
plunger down manually
2) Head is no longer working..... swop with one that is on another rad to
confirm

Tony

 

[chris_doran]

Fitting wrong end would not prevent the valve closing.

2 possibilities

1) plunger inside has jammed open..... remove head and test body by pushing
plunger down manually
2) Head is no longer working..... swop with one that is on another rad to
confirm

Tony

Re (2): To test the head, take it off and invert it. In the centre you
will see the pusher that moves the pin down. Note the position, stand
the head in a hot or cold place for a few minutes and see if the pusher
moves. It only moves a few mm, so make it a significant temperature
change.

2 more possibilities, especially if the head wobbles about:-

3) Ring screwing head to body of valve is loose. Open TRV fully and
screw it down -- Finger-tight will do -- then reset the TRV.
4) Rim on head which engages with said ring is broken, so it won't
tighten down. A bad explanation, but will be obvious when you try to
screw it up.

I have a lot of Landis & Gyrs which are notorious in respect of (4).
The rim is on the end of flexible fingers which are easily snapped off
if the head gets a bash. My own question: Does anyone know where I can
get replacement L&G or compatible heads (SE London)? Wickes and
Homebase don't seem to have them and the chap in Plumb Misspelled
barely looked up from the counter when I asked (do you have to wear
greasy overalls to get attention?).

Chris