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Finally Refilling the system - Check list and methods!

Discussion in 'Plumbing and Central Heating' started by dishman, 16 Sep 2019.

  1. dishman

    dishman

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    OK....in a few days I hope to be refilling my open vent heat only central heating system.
    It has one zone valve.

    It has been off and drained a lot longer than anticipated.

    I have manually flushed out nearly all the radiators...using a hose with good pressure.

    I am fitting a filter tomorrow hopefully if it arrives in the post.

    I just wanted to cross check the best method of refilling.

    Stop cock is tied off currently.

    The drain valve is at the lowest point of the system...under the floor actually.

    I assume the steps are to:

    1) let it refill from the tank
    2) Ensure the zone valve is at manual
    2) Have the last radiator open and bleeding, until it splutters. Then do each radiator in turn working up.

    My secondary questions are:

    Should I do a straight refill and be done? Or do multiple refills have to be done as a system wide flush, even if I have flushed each rad?

    Is a chemical cleaner really required?

    If I have flushed each radiator and the water coming out is pretty much clear....is a chemical cleaner counter productive as I am just potentially encouraging more crud to swilling around the system, which only requires a further drain.

    Obviously I will be adding inhibitor as I fill it....I just wanted to know the best method.

    Many Thanks.
     
    Last edited: 16 Sep 2019
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  3. terryplumb

    terryplumb

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    Check all drain cocks are closed.
    All radiator air bleed valves closed.
    All radiator valves are open (lockshields back to original settings)
    Check all radiator connections are sound.
    Clean f&e tank if need be.
    Latch valve manually open.
    Open cold water supply to f&e / commence filling.
    Go to lowest rad and bleed air out till water comes out. Carry on thru all rads.
    Checking all for leaks ( an assistant would be advantageous)
    Bleed the pump.
    If fitted ,bleed the cylinder coil.
    When you are sure all air is out of the system ,switch on the pump / run central heating. Checking for leaks again.
    If all goes well / no leaks ,then introduce inhibitor.
     
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  4. dishman

    dishman

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    Sounds good.

    If I am installing a filter. Is it best to introduce the inhibitor with one of ones you connect to the filter?

    I read that just pouring the inhibitor into the header tank after the system has filled reduces the chance of it getting around the system.

    I was planning to do it as it filled, but your "checking for leaks first" method does make more sense.

    And, from what you have written....you don't think I should do the method of filling the system....running it....seeing if that kicks up any crap.....draining it again....and refilling? I have read that as being an option.

    Regards
     
  5. terryplumb

    terryplumb

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    Sorry , missed the bit about system cleaning. Once the filter is fitted ,there is nowt to stop you from adding a cleansing chemical ,(follow the instructions that come with it ) .you can introduce it via the f&e tank ,but not when the thing is full. Make sure you don't have any leaks after re fitting all your rads ,as if you do ,you would probably have to drain down again and loose all the additives !! When all is leak Free ,just isolate the feed to the f&e ,drain out till the f&e is empty ,pour in the cleanser ,and open the isolator.
    The cleanser should be left in ,and the central heating ran for several days ,the filter checked / cleaned as required. ( make sure you fit the filter on the return NOT the flow ). You want the filter to catch the crud before it gets to the boiler.
    When the filter stops collecting crud ,drain out / flush thru a couple of times.
    Then add the inhibitor and fill up the system.
     
  6. dishman

    dishman

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    A few further questions on this.

    I had a few further decorating delays.

    1) Can adding a system cleaner be more trouble than it is worth. Meaning....if the system seems pretty clean other than a bit of dirty water....could adding cleaner end up loosening crud that did not need loosening (if you get what I mean) that the filter may not catch and end up bunging up the system somehow.

    2) When reattaching radiators. It seems the older connections have a metal washer (see picture) creating a seal between the radiator and the valve. Does this create a good enough seal on it's own, or should I put some boss white around it? When looking at videos, most seem to just reattach the radiator without issue.

    3) I replaced one of the valves with one with a drain off valve to make things much easier in the future. The radiator connection that came with it by default has a rubber washer/seal to make a good contact with the valve. Whereas as per above....the existing connection has a metal washer. I assume it is fine to keep it as it is.

    cupboards-7675.JPG cupboards-7679.JPG cupboards-7680.JPG cupboards-7681.JPG
     
  7. terryplumb

    terryplumb

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    Putting chemical cleanser into a clean system wouldn't do any harm ,and putting it into a system that isn't clean is what its for ,to aid cleansing.
    You have two different designs of valve,one with rubber washer and one without. The latter seals without any washer or compound. It relies on closely machined mating surfaces.
     
  8. dishman

    dishman

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    So does that mean it is inadvisable to mix and match?

    I assume that chances of them being similarly machined is low.
     
  9. terryplumb

    terryplumb

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    The radiator tail ,and the valve that is supplied with it ,are a pair. It wouldn't be good practice to mix one manufacturers valve ,with another manufacturers tail ,if that's what you mean by mix and match .
     
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  11. dishman

    dishman

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    Thanks, yeh I was unsure....although....for some reason I am not really a fan of the rubber washer solution....how well are they regarded, any long term issues with them?
     
  12. terryplumb

    terryplumb

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    None that I am aware of ,having said that , rubber does not have infinite lifespan.
     
  13. dishman

    dishman

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    A final question on this topic.

    Is there any issues in filling the system without all the radiators connected.

    There are a few rooms that will benefit from keeping the rads off the wall while final decorating work is carried out.

    There will be at least four active radiators.

    I assume as there is at least one on the system....it is not an issue.
     
  14. terryplumb

    terryplumb

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    If you intend to use a chemical cleanser ,all the rads need to be on and working.
    Not really a brilliant idea part filling an empty system with only a few rads connected. Pretty inevitable that you will have pockets of trapped air .
     
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  15. dishman

    dishman

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    hmm....good point.....

    Maybe I will get them all up and running....

    Supplementary follow-up. Most of the rads are existing and old....so likely to have crud in, although I have manually flushed them.

    One radiator is brand new.

    Is it worth running the system with the new one attached but isolated until I have flushed the existing system through?

    I assume the new radiator will be pretty clean inside. So surely it makes sense to run the existing system with cleaner first....drain....then allow water to flow through the new one with a dose of inhibitor.

    Or should it not matter.....I was just thinking about the system cleaner flushing crap through the new radiator.
     
  16. terryplumb

    terryplumb

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    Did you miss this ?
     
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  17. dishman

    dishman

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    Yeh I got that.......was just unsure about the new radiator.

    All on it is!
     
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