Leaking Immersion Heater

Discussion in 'Plumbers' Talk' started by Dubs, Nov 29, 2006.

  1. Dubs

    Dubs New Member

    Leaking Immersion Heater / Cylinder Connections

    I'm currently training as a plumber and I've come across this problem on more than one occassion.

    My current boss insists I use the fibre washer supplied and apply PTFE tape to the thread....However, I've often had leaks using this method.

    Am I doing something wrong or is there a better product than PTFE for this job
  2. Captain Leaky

    Captain Leaky New Member

    I like to use PTFE thread and top it off with PTFE tape but it should be OK either way. The over-use of jointing compounds etc makes it harder to remove the immersion in the future. One good tip is to tweak the immersion up a bit tighter once the cylinder is full of water. Use a proper box immersion spanner to make sure the leverage you apply is even.
  3. britishblue

    britishblue New Member

    My current boss insists I use the fibre washer supplied and apply PTFE tape to the thread

    Absolutely correct, but how are you tightening the heater? If you just turn the spanner until if feels tight, it will always leak. You have to use the same method for tightening as that for removing. You tighten by hand and then give the spanner several light taps with a hammer and you will see that it turns further. Remember only light taps.

  4. Dubs

    Dubs New Member

    Ok, I'll give that ago...
  5. tgs

    tgs New Member

    I use a box spanner and a chain wrench for more leverage. You need that or as BB says you need to tap the spanner. Fibre washers swell slighty with water and so increase the seal. They also release easily even when very old, that and the PTFE tape means that in future the immersion heater should release relatively easily.

    I actually use the thinnest smear of silicon grease on the threads of the boss to help aid tightening up. Works every time.
  6. M.I.G.

    M.I.G. New Member

    > Am I doing something wrong or is there a better
    product than PTFE for this job

    yeah shove some o' that lovely Boss White on it..!

    (it smells nice too)
  7. tgs

    tgs New Member

    yeah shove some o' that lovely Boss White on it..!

    It's because of that stuff that I spend more time explaining to a customer what might happen when I try to take out the immersion heater than I actually spend taking it out.
  8. plummit

    plummit New Member

    Ptfe on threads, actually does help in the removal of immersion heaters at a later date. use any washer, god knows I have made my own, not a lot of water pressure on vented cylinders, in most domestic systems.
  9. RenewableEnergyMan

    RenewableEnergyMan New Member

    Heh, Its not often that I get to answer the tough ones with an easy answer.......

    we fit upwards of 250 immersion heaters a month to our products and we've tried the lot - thread sealant/paste/fibre washers, but the best answer we have found is a neoprene(squishy rubber) 'o-ring' that seals the immersion heater against the flange on the end of the immersion boss on the cylinder.

    They are such a good seal that even I (a non hands on - they dont let me near the shop floor salesman type) have fitted an immersion heater, hand tight - no tools - onto an unvented cylinder and had it pass a pressure test at 5.25bar.

    Nuff said.

    on a related note, we get a few cylinders a month returned because of 'faulty' immersion heater connections - they almost always turn out to be crossthreaded where the immersion heater (which is brass) isnt threaded properly onto the thread on the cylinder (copper) then tightened up with an immersion spanner cutting a new thread that cant be sealed. This is easily avoided by pressing the heater against the boss and turning ANTI clockwise till the threads 'click' into place, then screwing up as normal. Sorry to preach - most of you guys know this old trick but it will save a lot of grief if you do this with every immersion.


    ps. the O'rings are available from HD Howden in Glasgow, but you might have to buy 100 or so to get them.
  10. Captain Leaky

    Captain Leaky New Member

    HD Howden
    10-12 Belgowan St
    ML4 3NS
    01698 573 100

    Friends of D ick Puller are they?
  11. M.I.G.

    M.I.G. New Member

    - White + Green
  12. rocketron

    rocketron New Member

    I have a 2&1/4 bsp tap for emersion heater threads, anyone wont it when i retire.
  13. RenewableEnergyMan

    RenewableEnergyMan New Member


    I'll take it - they cost over £150 new :)

  14. rocketron

    rocketron New Member

    30 years ago i converted a 20ft x 15ft glue tank. It had a steam jacket around it, i welded 8 steel plates with tapped holes into the jacket, and replaced the steam with oil. Our toolmakers made the tap and i have it, and its been handy often.
  15. Dick Puller

    Dick Puller New Member

    Thanks CCM for the good tips. I'll bid £30 for the 2.25'' tap. Oh sh.te have we started another eBay???
  16. Dick Puller

    Dick Puller New Member

    Red White + Blue 'Anon'

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