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Where did I go wrong draining my Combi Boiler System?

Discussion in 'Plumbing and Central Heating' started by Mr Sparkle, 11 Jan 2019.

  1. Mr Sparkle

    Mr Sparkle

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    To drain my system, I attached a hose to the rad drain valve

    I then opened up the rads to allow air out

    After waiting over 2hrs for the water to drain.. I went to add some inhibitor into my towel rad (by opening the valve on top (not the air side)..

    I'd barely added 100ml when the water in the rad shot up all over the floor.

    What I want to know is why this happened?

    FYI - I never turned off the main water supply... and I live in a block of 20 flats with an individual combi boiler..

    Does anyone have any advice on getting inhibitor back into the system in this case?
     
  2. FiremanT

    FiremanT

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    Was it not the inhibitor, rather than water, spraying out? Normally a case of pouring in quicker than the rad is allowing the fluid to flow through. You don't need to isolate at the stopcock.
     
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  3. cross thread

    cross thread

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    isolate the towel rail, remove the top air plug siphon a litre out and pour in the inhibitor, replace plug open valves to towel rail and repressurise system
     
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  4. Mr Sparkle

    Mr Sparkle

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    It was mainly inhibitor, but the inhibitor/water remains by the top airplug

    Great idea! Thanks

    A couple things.. By isolate do you mean 'Shut off the lockshields?'

    Also, what can i use to get a litre out?
     
  5. dilalio

    dilalio

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    Nozzle from a spray bottle and squirt it into a bucket or you can use a bit of pipe using your thumb to create a vacuum and bail it out.

    Open up the other end (air vent) too as this will make it easier to pour inhibitor in by preventing a vacuum.
     
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  6. Ian H

    Ian H

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    When I poured it into mine it all came out because the holes into the towel rail tubes were higher than the bottom of the vent plug. I had to raise one side a bit.
     
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  7. Mr Sparkle

    Mr Sparkle

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    In the end i cut a piece of my garden hose (long and flexible)..

    stuck this in the radiator and then attached my wet vac to the end of the hose and it drew all of the water out

    Your post provided the inspiration, so thank you..

    Inhibitor's now in the system and jobs a good'en :D:D
     
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  8. dilalio

    dilalio

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    The mighty wet vac... Every home should have one ;)
     
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