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Discuss radiator in bathroom in the Plumbing Forum area at

  1. kakawak

    kakawak New Member

    hi guys,

    im looking to cut copper pipe underneath floorboards leading to the imperial radiator thats currently there. can someone advise on best solution to my problem?

    i cant bung the tank because whoever installed the water tank in the loft leaves me no access to get into it above. the only way i can see is using a selfie stick with a phone to view any issues from above :(

    i know your going to say just drain the system etc... but i also have another problem.. whoever installed the small radiator in the dinning room has the drain valve behind the skirting board :/ i have been told that these drain valves are temperamental meaning it might spring a leak or something and due to position its not something i want to really get bogged down with!

    so, is there a way to cut the pipe with the water still being in the system? im assuming that my pipe are imperial and was told to use an imperial to metric straight coupler 15mm. i will upload photos to show what i intend to do, hopefully my diagram will help :)

    you will see in the photo how my current waste was setup...notice the ubend being higher at one end!!!! lol it was terrible.

    what is the tolerance of a drop from bath to u bend under floorboards to stop a syphoning effect because if i opt to have my s bend above floor this is how it will look (see photo) or i can drop straight down beneath floor boards and have my ubend there :) please advise.

    i know im asking alot of questions for my first post so please forgive me!!!

    thanks for help in advance







  2. sammathias

    sammathias Plumber GSR

    i would either do it live as its only tank feed...wouldn't recommend tho. bung the tank outlet and vent, freeze pipework or drain down...(that drain off on the valve in the skirting boards are very reliable...)

    nothing wrong with that bath waste?
    • Like Like x 1
  3. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Freeze the pipe
  4. kakawak

    kakawak New Member

    yea but would you opt for the ubend under floor with a drop from bath? im going to leave a hatch under bath for access my worry was regarding the drop!

    im definitely using the freeze option...any cheapish recommendations on brand and ease of use? what is the average time from frozen to thaw out when cutting pipe? if im only cutting 2 pipes how many cans will i need?

    if i hook up my sink to 32mm plastic pipe (pushfit) using a bend going down with it connecting to a 40mm pipe, what is the best way to do this? cant see any 32mm to 40mm pushfit reducer in a bend format. is the only way to use solvent weld attachments?

    can i reuse 15mm plastic pipe that was used in my old bathroom? if not, what do you recommend as i will be using plastic on copper pipe once i use the plastic pushfit metric to imperial coupler. do i need to wrap the plastic pipe in the wall once i chase it?

    Last edited: Jul 12, 2018
  5. sammathias

    sammathias Plumber GSR

    Well a deepseal trap would be better 75mm. Or you could just fit a hep20 waterless trap.

    I tend to just use artic spray freezer 500ml can will do two seperate 15mm pipes, plug should last 20-30 minutes but I never hang about. I would turn valves off and take off rad then do all your necessary pipework with valves on the ends leaving the final connection to your existing pipe before starting to freeze so it's a quick turnover. Doing one pipe at a time

    Not quite sure what you mean about the 32/40mm pipe? Only tend to use solvent weld. But you can cut a 32mm socket off a fitting and it will fit into the 40mm fitting acting like a reducer...

    Hate plastic pipe but for DIY I suppose it's acceptable. No harm in reusing pipe but I wouldn't reuse fittings too much...don't have to be protected in wall.
  6. snowhead

    snowhead Well-Known Member

  7. kakawak

    kakawak New Member

    ok, what do you think of this so far and be it passable?

    i used the arctic freeze to cut pipe and replace with pushfit plastic. what a godsend that stuff is :)


  8. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    That joist looks wrong (middle two and the right one)
  9. kakawak

    kakawak New Member

    the joists were like that when i lifted the floor and it looks like its been double strapped however, i know you and others might say to get them replaced but i am in no position financially to to do that.

    the floor seems to be sturdy with no movement so fingers crossed.

    whats the best way to test the waste pipe without the bath in place....just pour a bucket of water down? also, if i turn on central heating will this be a good test with the pipes that are chased in the walls?

    can i cover the plastic pipes with plaster or do i need to wrap them first?

  10. sammathias

    sammathias Plumber GSR

    Yeah good effort, just... Are you fitting a new rad? Pipes seem quite high up pipe up I meant to positions where rad valves connect rad so you don't have to freeze are you going to freeze again with pipework hidden?
  11. sammathias

    sammathias Plumber GSR

    No need to protect plastic in plaster wall and asking as system is filled up/pressurised the joints are sound
  12. kakawak

    kakawak New Member

    hi sam,

    the radiator in question is this...

    Mode Hardy anthracite heated towel rail 1000 x 500

    what is the required height? i could probably push the pipe down a 2" if need be... do you mean if i decide to lower them, then how will i freeze the pipes if i decide to change height? if so, the answer would be no to that. better to get it right now than regret it later. if i lower the pipes by a couple of inches, i still have 18mm plywood and tiles to go on top of floor so that will raise it another inch. i didnt want my towels dragging on the floor as i have 3 kids :)

    Last edited: Jul 26, 2018
  13. sammathias

    sammathias Plumber GSR

    No required hight mate. The point I was getting at is your going to have to freeze pipework again to pipe up towel rail? Could have saved yourself a can of freeze
  14. kakawak

    kakawak New Member

    should i have just connected and wall mounted radiator before i capped? the reason i left it like that was so i could tile the wall easier. what is the correct procedure for future reference?

  15. sammathias

    sammathias Plumber GSR

    It will be neater the way you have done it as you say you are tiling the wall first. I tend to know the dimensions and positions of where rad valves will finish so I pipe it up with rad valves attached and closed to save draining down again when fitting the towel rail. You just have to freeze it again the way you done it.

    How did the freezing go anyway, did you leave it open ended for long or was it a quick turn over! I use them kits alot but still don't fully trust the guide times!
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