Thermostatic valves for imperial radiators ?

[IJWS15]

Just to addd to what has been said as an amateur I have never seen a radiator with metric threads.

Worked on systems from the 1960s to 2003 in houses we have lived in over the last 30 years.

The brass tail (may be chromed and comes with the valve) will be 1/2 BSP taper as will the hole in the radiator. Tails frequently don't fit other valves so use the tail which comes with the valve.

Never even check when I buy a radiator that I have picked up an imperial and never been surprised.

Now does your plumber mean you have 1/2 inch copper tube instead of 15mm? If this is the case it is an easy job to replace the last couple of inches of pipe with 15mm using a converter. There may be kits available to put 1/2 inch tube into a 15mm compression joint on the valve - long time since I had the problem and cannot remember which is bigger (1/2 or 15mm).

 

[tonybhoy]

long time since I had the problem and cannot remember which is bigger (1/2 or 15mm).

They're both the same size mate however old heavy gauge copper isn't and can be up to 18MM od but don't think the OP is talking about pipe that old.

 

[Nige F]

Screwed and sweated copper That would be worth totting

 

[doitall]

Like that Noge F, Oh how I would like some of that stuff in the scrap box nowadays.

 

[PocketGuy]

Hi all
I know this has been covered already, but I couldn't quite see my combination of bits, so just looking for clarity.

This is a metric TRV/imperial rad tail/pipework question.
Fitted TRVs before at my last two places, but always metric-for-metric. As will be obvious, I'm no pro...

Acquired some new and unused 15mm Drayton TRVs free, so naturally would like to use them
Here's what I know:

Used a basic set of calipers for measurements (metric and imperial scales).
Boiler 7 years old but rads fitted more than 20 years ago.
All vertical pipes into manual valves seem to have 1/2" OD.
The vertical part of the new valve seems to accept 1/2" OD pipe (is it called 15mm because that's its OD??), and the tail provided with each TRV seems also to be for 1/2" (the thread OD for the rad tail end measures 18mm).

The problem: All rads have 18mm (3/4"?) OD pipes feeding into them and the thread OD of the tail is 1" as near as I can measure (the nut for the tail is about 1/4" proud of the rad so the threads are accessible).

Obviously the 'fix' is at this end, but the local diy shops were as helpful as a chocolate fireguard...

Any experienced feedback/help much appreciated

15mm TRV's come with a 1/2BSP tail and 15mm fittings.

1/2BSP valves(imperial) come with a 1/2"BSP tail and 1/2" BSP fittings

1/2" British Standard Pipe threads will not fit onto a METRIC 15mm threads, they are physically different

Drayton supply both imperial and metric valves. If in doubt speak to there tech cell on 0845 130 7722

So you are saying I can't strip an old radiator and fit a new valve

Absolute rubbish. I have fitted thousands of radiator valves, old and new in the last 50 years, and not had a problem yet.

 

[compheat]

Your best bet is to isolate and drain down your system and then remove a valve to see if it will fit. As all the other tradesman have said before most rads are 1/2" bsp the only rads you get that are 3/4"bsp are usually large commercial ones. The pipework should be 1/2"or 15mm copper,
If they are 3/4" or 22mm copper which is not the norm on Domestic installs then you've got a problem

 

[Nige F]

that 3/4 or 18 mm bit is a half inch BSP tail screwed into the rad ...and has to come out with a bit of heat on it and the special tool pictured some posts back then the Drayton tail Will go in

 

[kirkgas]

Your best bet is to isolate and drain down your system and then remove a valve to see if it will fit. As all the other tradesman have said before most rads are 1/2" bsp the only rads you get that are 3/4"bsp are usually large commercial ones. The pipework should be 1/2"or 15mm copper,
If they are 3/4" or 22mm copper which is not the norm on Domestic installs then you've got a problem

the only prob with this would be going back to the shop to buy a 3/4"x1/2" bush for each valve

 

[kirkgas]

Hi,

I have a new boiler but a house full of imperial radiators, some of which are curved (due to window bay) and likely to be expensive to replace the whole set.

I need to fit thermostatic valves but everything on the market seems to be metric.

Is there a imperial to metirc convertor or imperial thermostatic valve option so i can avoid replacing radiators?



c'mon webless post a pic so we can all look smug and be right

 

[WDIK]

Like that Noge F, Oh how I would like some of that stuff in the scrap box nowadays.

20 thread copper John?

got some in the garage for drifts

 

[PocketGuy]

Hi again.
Just thought I'd feedback my experience regarding my imperial-to-metric TRV issue.

I took a trip to Plumb Centre and got some 3/4" to 1/2" bushes just in case, drained the system down and, sure enough, the first 2 rad tails I took off (after much grunting, heat and a large wrench!) were 3/4". All of the house rads bar one were 3/4", and the reducer solved the problem.

Thanks again to compheat, Nige F and kirkgas for your advice.