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Do I need to drain?

Discussion in 'Plumbing and Central Heating' started by essex123456, 20 Jul 2018.

  1. essex123456

    essex123456

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    i am about to fit a new towel radiator. It is slightly different to the old one. And I need to move the valves and modify the pipe work.

    We have a combi boiler, do I need to drain the system down? The towel radiator is on second floor and boiler is downstairs or can I get away with shutting the power off and just taking the old valves off to do my amendments?

    Thanks
     
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  3. terryplumb

    terryplumb

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    You need to drain down the pipework to at least a lower level than the pipework that you intend to work on.
     
  4. essex123456

    essex123456

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    Thanks, Can I shut the upstairs rads off and then drain enough to lower the level in the pipe I need to adjust?
     
  5. terryplumb

    terryplumb

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    Each radiator has two valves ,one is called a lockshield , and each lockshield valve is set at a particular part open position ,which may well differ from one rad to another. This is called balancing and the installer ,when commissioning the central heating system, would have set these positions. My advice to a diyer would be to leave them alone and drain down from a ground floor drain cock ,opening only the air bleed valve on all upstairs rads ( one at a time whilst draining). This will aid draining as you are allowing air into each rad. You will of course loose a large amount of inhibitor ( assuming your water actually contains some ) but its relatively cheap to buy and adding it is a must. And as you are draining the water out you are less likely to get any nasty wet surprises !!! Be wary though ,as a small amount of water may still be present ,locally in the pipework you cut into, as any pipework that does not have a continuous fall will still hold water. This method will still leave most downstairs rads full of water however.
     
  6. essex123456

    essex123456

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    Can I use pipe freeze?

    If I locked each rad off and drained would that work? I only need to drop the height by a couple of inches. Drawing the rads as welll seems extreme.
     
    Last edited: 26 Jul 2018
  7. dilalio

    dilalio

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    Drain it down.
    If it was a school or church in the middle of winter, one would look at local freezing, for a normal house with a combi, in the middle of this hot weather, it's a no brainer!

    Would also be good maintenence opportunity to flush it out, change the water and inhibitor.
     
  8. FiremanT

    FiremanT

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    You can do whatever you like. It is your house. But why ask for advice, then argue?.
    FFS, draining down takes 15 minutes, assuming a working drain cock . And even that 15 mins is nor wasted - you carry on with other stuff.

    They say no question is stupid.

    I am not so sure.....
     
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  9. Might as well drain it all out,try not to make (n)hard-work for your self.

    whilst cutting into the pipes there may be some residual water left in the pipes so have a means of collecting it or use towels.like any job allow your self enough time and extra time for any remedial work :idea:

    Or get a pro in :D
     
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  11. Gammy leg

    Gammy leg

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    Hijacking this thread a bit but when it comes to refilling the central heating system after draining down a radiator, will a combi boiler automatically de-air the system after it has been refilled and brought up to pressure, or would the rads have to be bled as with other types of boiler?
     
  12. FiremanT

    FiremanT

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    You need to bleed
     
  13. dilalio

    dilalio

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    That's a bit harsh mate! ;)
     
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  14. essex123456

    essex123456

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    I'm not arguing, I was just querying if I needed to drain down gallons of water when all I want to do is whip a rad valve off and replace with an isolation valve.

    Some advice is really helpful, others are just rude.
     
  15. endecotp

    endecotp

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    The “gallons of water” will be considerably cheaper than a pipe freezing kit.

    Freezing is, I think, a last resort for cases when valves have failed or similar. It also has the disadvantage that you have to complete the work before the freeze melts; this could be a challenge if you are inexperienced!

    I think the real plumbers (I am not one!) would not like the idea of isolation valves in central heating circuits.
     
  16. essex123456

    essex123456

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    Hi thanks for your advice.

    I'll drain down the freezing was just an idea.
     
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