Hi there..

I know there are a few posts in this group realting to this topic, but
I wanted an idea of doing the whole job...

I've got a pretty old gravity ho****er setup with 15mm pipes to the
rads. I have already bought a few thermostatic vavles and need some
advice on fitting.. I've found a drain point near my boiler - and I
know I'll need to protect the carpet when I loosen the pipes to the
rads...but here's a few things I'm not sure on..

Do I just drain down the whole system and then start fitting the
vavles?
Do I need to remove the radiator to fit the valve?
Each rad has a control knob to turn off the water to the rad - do I
replace these with the vavles, or do they go on the other side of the
rad?
Should I refill the system with an inhibitor and cleaning solution?
Do I need to fit the valves to radiators in any order and do I need to
carry out any procedure to refil other than make sure all vavles are
fitted then turn on the water?

Thanks alot!

Simon

In article ,
Simon C wrote:
Do I just drain down the whole system and then start fitting the
vavles?

Yup.

FWIW, it's worth buying good quality TRVs from a plumber's merchant rather
than shed own brands. Drayton is a decent make. TRVs don't last for ever,
but good ones might have 3-4 times the life of others but don't cost that
much more.

Do I need to remove the radiator to fit the valve?

No. But you might have to replace the short pipe going into the rad,
depending on the design of the TRV - but it comes with the TRV, so is
simple to see if it's different.
You need the correct tool for this - an allen key that fits inside the
pipe. Not expensive.

Each rad has a control knob to turn off the water to the rad - do I
replace these with the vavles, or do they go on the other side of the
rad?

You need to check the instructions with the TRV. Some must go on the input
- some don't matter.

FWIW, the two original valves are identical - just the knobs are
different. The idea being one is preset to balance the system and is
fitted with a cap to prevent tampering, the other to turn off the rad or
adjust by the householder if needed.

To determine which is the input, feel the pipes when the system is first
switched on. The feed will get hot before the return. Hopefully this will
be the side with the user adjustable valve, but I'd still check. A TRV
fitted to the 'wrong' side will likely be noisy and may not work properly.
If the system was working well before, try not to alter the preset valve,
or if you do, count the number of turns so you can put it back to where it
was afterwards. The procedure for the adjustment of these from scratch (if
needed) is covered in the FAQ under balancing the system.

Should I refill the system with an inhibitor and cleaning solution?
Do I need to fit the valves to radiators in any order and do I need to
carry out any procedure to refil other than make sure all vavles are
fitted then turn on the water?

The rads, of course, will need bleeding of air.

I'd fill with plain water, use for a couple of days to check for leaks,
then drain down enough to add the inhibitor.

You might well get an airlock. If it's only say one rad effected, turn the
others off and run the pump at max - this might clear the airlock.

The other way is to connect a mains water hose to the drain point and
force water back into the system that way. That should cure the airlock.

--
*If at first you do succeed, try not to look too astonished.

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

In article ,
"Dave Plowman (News)" writes:

No. But you might have to replace the short pipe going into the rad,
depending on the design of the TRV - but it comes with the TRV, so is
simple to see if it's different.
You need the correct tool for this - an allen key that fits inside the
pipe. Not expensive.

I found a 1/2" cold chisel with a hexagonal shaft to get the spanner
on was just perfect.

--
Andrew Gabriel

In article ,
Andrew Gabriel wrote:
No. But you might have to replace the short pipe going into the rad,
depending on the design of the TRV - but it comes with the TRV, so is
simple to see if it's different.
You need the correct tool for this - an allen key that fits inside the
pipe. Not expensive.

I found a 1/2" cold chisel with a hexagonal shaft to get the spanner
on was just perfect.

I tend to use one from my socket set.

The correct tool gives you the thingy for fitting the bleed screws too,
though. And they're a bit more difficult to find a bodge for. ;-)

--
*If you can read this, thank a teecher

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

On Mon, 13 Sep 2004 10:11:54 +0100, Dave Plowman (News) wrote:

No. But you might have to replace the short pipe going into the rad,

Otherwise know as a "tail".

depending on the design of the TRV - but it comes with the TRV, so
is simple to see if it's different.

I don't think I've ever found a tail that matches a new valve, TRV or
ordinary. Thats on the various vintage rads here and in my Bristol
flat, they where only about 10 years old when I swapped 'em.

When changing tails you'll need some PTFE tape to wrap around the
threads to seal them. Half a dozen or so turns in the direction that
means it stays on the thread and is not pushed off by the turning.

You need the correct tool for this - an allen key that fits inside
the pipe. Not expensive.

But the correct modern doesn't fit imperial tails. Found that out last
week. B-( Had to grind a good 1/2mm off each face of one end to get
it to fit. Oh and tail thread sizes haven't changed. B-)

--
Cheers
Dave. pam is missing e-mail

In article om,
Dave Liquorice wrote:
You need the correct tool for this - an allen key that fits inside
the pipe. Not expensive.

But the correct modern doesn't fit imperial tails. Found that out last
week. B-( Had to grind a good 1/2mm off each face of one end to get
it to fit. Oh and tail thread sizes haven't changed. B-)

Good grief. I'm on my third set of TRVs in this house, but all are the
same. Changed to the current set only last year. Have they changed since
then, or before I installed the first lot?

--
*You're just jealous because the voices only talk to me *

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

On Mon, 13 Sep 2004 23:53:35 +0100, Dave Plowman (News) wrote:

But the correct modern doesn't fit imperial tails.

Good grief. I'm on my third set of TRVs in this house, but all are
the same. Changed to the current set only last year. Have they
changed since then, or before I installed the first lot?

I'm refering to the hex hole in a *very* old tail. At a minimum I'd
say 20 years old a more realistic date might be 30 years. This part of
the house is plumbed in imperial pipe, when did metric pipe come in?

makes mental note to buy some imperial olives, having being "got" by
the damn stuff again

--
Cheers
Dave. pam is missing e-mail