3/4 inch radiator tail?

Discussion in 'Plumbers' Talk' started by dvddvd, Jan 17, 2019.

  1. dvddvd

    dvddvd Well-Known Member

    Hi does screwfix sell 3/4 inch radiator tails ?

    I have 1/2 inch valve on one side and 3/4 inch valve on the other.
    I want to change radiator and it comes without tails, why do they use 3/4 on one side and 1/2 inch on the other ? I dont want to drain the system and change valves ...thanks
     
  2. dcox

    dcox Screwfix Select

    Perhaps older systems needed larger pipework to get the hot water around. I changed an old 3/4 valve recently and just put a 3/4 to 1/2 bush in the rad first then used a standard 1/2” tail and valve.

    I think you’re going to have to change the 3/4” valve to suit your new rad.
     
  3. The tails are 1/2" it is the union joining the rad valve that is 3/4".
    [​IMG]
     
    Heat and WillyEckerslike like this.
  4. dvddvd

    dvddvd Well-Known Member

    Hi the bit that goes into the radiator is 1/2 but the valve is 3/4 union nut ? Can not see any on Screwfix just 1/2 valves and tails ? thanks
     
  5. dcox

    dcox Screwfix Select

    Ah. The example I used had a 3/4” threaded tail, not just the nut. If it’s like the pic above then you can take the tail out of the old radiator and reuse it (usually an internal hex to undo) and so keep the valve.

    TRVs all seem to use 1/2” nuts and lockshields are either 1/2” or 3/4”. You do quite often see one of each on a radiator. The 3/4” style do make removing and refitting a rad easier as they mate face to face rather than with a male and female parts that can be difficult to pull apart. Some 3/4” style valves use an O ring to seal which seems to work well.
     
  6. dvddvd

    dvddvd Well-Known Member

    Hi yes the 3/4 inch union nut ?
    I want to keep the valves so its a tail with a 3/4 inch union nut i need? thanks
     
  7. dcox

    dcox Screwfix Select

    Why can’t you take the tail and nut off your old rad and reuse it?
     
    Heat likes this.
  8. dvddvd

    dvddvd Well-Known Member

    Ill try, i just thought new radiator i may as well buy a new tail ? why dont they use/sell them anymore ?
     
  9. dcox

    dcox Screwfix Select

    Or buy the part that Deleted member 11267 has uploaded and just use that tail and nut with your old valve.
     
  10. dvddvd

    dvddvd Well-Known Member

    thanks but is the pic a 1/2 nut on the valve ?
     
  11. dcox

    dcox Screwfix Select

    I’m not aware that you could buy just the tail...
     
  12. dcox

    dcox Screwfix Select

    No - that’s 3/4”.

    1/2” thread that goes into the rad. 3/4” nut. It is a bit confusing I must admit!
     
  13. I have posted a picture of one and a link to one.
     
  14. dinkydo

    dinkydo Screwfix Select

    1F54219F-1969-491D-9891-B355218B6E3B.jpeg You will find that 3/4” tails are available just google it, (Not to say your existing valves will fit these) you will see them on Amazon and other places, or you can use a reducing Bush as shown & then a standard 1/2 tail, you can get these in steel or brass/copper/chrome
     
  15. Heat

    Heat Screwfix Select

    3/4” tailed valves were the best valve back in the day.
    The flange joint meant the pipes needed almost no movement when rad was ever removed, or valve replaced.
    The newer 3/4” tailed valves are often just cheap standard valves, but still same idea.
    The only disadvantage compared with the 15mm tailed valves is you couldn’t extend the tail length distance as easy.
    A rad valve tail key will remove the old tail.
     
    dinkydo likes this.

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