JG Speedfit stop end on radiator valves

Discussion in 'Plumbers' Talk' started by DIY_Has123, Nov 17, 2021.

  1. DIY_Has123

    DIY_Has123 Member

    One question though, boiler pressure is showing 2.5 bar now. Was showing f75 fault pump/water shortage which I have seen before but manually turning the pressure back up using valves below the boiler resolves this.

    Is this a normal or safe pressure for the combi boiler (valliant)?

    I'm assuming its all safe now (in terms of flooding and leaks) once the TRV and valves are securely fitted on?

    Definitely taught me a lesson and got me more cautious and nervous too.
     
    Last edited: Nov 18, 2021
  2. Jimbo

    Jimbo Screwfix Select

    F75 is caused by dirt in the pressure sensor, it's a cheap part and easy to replace.
     
    pppmacca43 likes this.
  3. Mr Rusty

    Mr Rusty Screwfix Select

    When fitting flooring around radiators you can cut a wedge (cheese) shaped piece out the floor at the back of the hole. Because of the wedge shape the piece will push back in real tight taking up the width of the saw blade. Done carefully it is invisible.
     
  4. pppmacca43

    pppmacca43 Super Member

    we’ve also had this fault at work several times, mostly caused by pressure sensor as you say but other causes can bring this fault up too. A faulty pump in the boiler so no pressure change is detected. Also with faulty expansion vessels causing the pressure to rise to high, so no pressure change is detected. I think the presssure being to low can also bring this fault up.
    I would depressurise the system to between 1 and 1.5 bar and reset it and see if it happens again.
     
  5. terrymac

    terrymac Screwfix Select

    2.5bar is too high. With system cold ,set pressure to 1 bar. Use a drain cock to let water out to drop pressure.
     
    pppmacca43 likes this.
  6. DIY_Has123

    DIY_Has123 Member

    I got the f75 fault when pressure was at 0.9 bar.
    Not sure where the drain cock is located. Will it be below the boiler?

    Will bleeding the other radiators that are connected in the house lower the boiler pressure?
     
  7. Jimbo

    Jimbo Screwfix Select

    Drain anywhere
     
  8. terrymac

    terrymac Screwfix Select

    Yes ,bleeding rads will drop pressure ,but takes a while. Drain cocks ,assuming you actually have any ,can be part of certain rad valves ,or on pipe runs ,on the lowest part/s of the system. You can go above 1 bar ,but no higher than 1.5 bar, if needs be.
     
  9. DIY_Has123

    DIY_Has123 Member

    Bled one of the rads downstairs and pressure is down to 1.8 bar. I reckon will get below 1.5 if I bleed it some more.

    This valve here has a slight weeping leek btw. The olive seemed lose on it and just slipped out yesterday. The olive on TRV seemed more secure. How many PFTE tape turns does it normally need?
     

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  10. pppmacca43

    pppmacca43 Super Member

    No ptfe on olives. I would put a small smear of Lsx around an olive normally. It may just need tightening up of it feels loose
     
  11. dcox

    dcox Screwfix Select

    No ptfe at all on those. The tail that’s screwed into the rad needs it - around 20 wraps if it’s the tape, less if cord.
     
    pppmacca43 likes this.
  12. DIY_Has123

    DIY_Has123 Member

    Yeah I've tightened it and still seems to weep. Do olives sometimes need replacing because they've become loose? Could that be the case I wonder...
     
  13. just pumps

    just pumps Screwfix Select

    How can an olive become loose, it is a basic crimp/compression fitting.
     
  14. pppmacca43

    pppmacca43 Super Member

    It may have been knocked, or twisted and sometimes they just won’t reseal. In that case best thing to do is replace. If the olive has been over tightened and has squished the pipe in then u may need to cut a socket below but generally you can just get the old one off and replace it. I would reccomend getting some LSX for when u are doing compression fittings, you just smear a bit around the olive when it’s on the pipe, it’s a jointing compound and is good stuff.
     

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  15. DIY_Has123

    DIY_Has123 Member

    @pppmacca43 yeah I think the olive may be fine but the black brass pipe has probably become swished slightly or because the black coating has chipped off and now causing the olive to be looser and slip out easily. Might be better to replace it in any case.

    What do you mean by cut a socket below btw?

    Yeah have the lsx tube used it on the compression elbows. Hate the smell lol
     
  16. pppmacca43

    pppmacca43 Super Member

    I meant that sometimes olives are overtightened so much that the only way to repair is to cut the pipe below and use a coupler (socket) to put a new piece of pipe in
     
  17. terrymac

    terrymac Screwfix Select

    What's all that gunge around the compression elbow in your last pic ?
    The black coated ,brass ,pipe will likely be harder than copper pipe ,and will most likely need more torque when tightening the compression olive.
    Decent length spanners required !!
    If the olive is loose it's not likely to have been deformed ,or crushed the pipe.
     
  18. pppmacca43

    pppmacca43 Super Member

    Looks like LSX has been used around the outside fittings. I never noticed that earlier. For the OP - that isn’t the correct way to use it, it is only needed on the olives and only a smear around them.
     
  19. DIY_Has123

    DIY_Has123 Member

    Yeah hands up I admit went a bit overboard with the LSX. Originally applied it to the compression elbow olives and tightened....after either you @pppmacca43 or @terrymac recommend LSX couple weeks back.

    But then I thought to apply between nut and pipe as an extra precaution. Will it do any harm?
     
  20. DIY_Has123

    DIY_Has123 Member

    Yes the black coated brass pipes are definitely harder.

    Anyway used water pump pliers to hold the valve and a spanner to tighten the nut, gave it another half turn or so and seems to have done the trick. No more weeping for the past hour or two. Fingers crossed.

    I rate you plumber pros, quite fiddly, tricky and precarious it seems to me these fixings. And you guys deal with them daily lol
     

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