Return pipe luke warm on radiator

Discussion in 'Plumbers' Talk' started by bond007, Oct 25, 2017.

  1. bond007

    bond007 Member


    Need a bit of assistance, i have 1 radiator upstairs which doesn't get piping hot like the rest.

    It should be free of sludge as i recently replaced it along with new TRV and lock shield etc.

    The TRV pin is fine, lockshield is fully open. all rads are balanced and still same. I did turn off all rads from lock shield apart from this 1 and it did get hot. But didn't check return pipe on the Rad to see if that was hot too.

    I think its a case of either a kink in the pipe work from the onset or sludge in the return pipe on that rad.

    How can i eliminate what it is?

    Also if it sludge in that pipe, how can i clean it out without having to do a power flush ?

    Its a 10mm pipe by looks of it.

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  2. KIAB

    KIAB Well-Known Member

    Power flushing isn't the solution to all problems,can also cause problems, so first thing I do is fit a magnetic filter,if your systm doesn't have one, the Magnaclean Pro 2 among the best to your system, this will collect the crud within your system.

    Personally I hate small bore piping for central heating can give you so much grief, is the whole heating system 10mm pipe or just a length to this radiator.
    Could switch off boiler, remove radaitor, then open valves & drain water into a bucket, might just shift something.
    If you fitted magnetic filter you could does system with Sentinel X800 or Adey MC3 cleaner let run around system for a few weeks, also going around with rubber mallet & tapping radiators will also help to dislodge any crud, this will certianly remove any crud,then thourghly flush system, refill & add Sentinel X100 or Adey MC1+ inhibitor.
    You would need to check filter daily for the first week, then a couple of times for a week or two, then once or twice a year.

    You have balanced system correctly.:)
    Last edited: Oct 25, 2017
  3. terrymac

    terrymac Well-Known Member

    If you close off all other radiators ,not by the lockshields but their trv's, and your problematic radiator then works fine it is most likely a balancing issue.if it works the pipework can't be blocked. Obviously you need to have both valves open on the problem rad when doing the trial
    KIAB likes this.
  4. KIAB

    KIAB Well-Known Member

    terrymac likes this.
  5. bond007

    bond007 Member

  6. terrymac

    terrymac Well-Known Member

    Just close the trv's .the lockshields are used to balance the system upon initial commissioning. You should not alter their original settings ,if you do you ,must return each one to its original position X amount of turns .if you don't you get exactly the problem you have with one or more rads not getting their fair share of the hot water from the boiler.
  7. Bond, you have tried turning off all the other rads using their lockshields (groan - did you note EXACTLY how far OPEN they were originally so's you could return them there?) and this rad did then heat up.

    That's no surprise as it would have had to have been totally blocked for it not have heated up.

    But this doesn't mean that the pipes to/from it aren't partially blocked, and this could still be your issue as well as it being a case of it all needing balancing. So we simply don't know if it's down to a partial blockage.

    When you removed the old rad, was there any sludge in it? If so, how much?

    If you really suspect a partially-blocked pipe is the issue, then this is what I would do - have done - to fix it.

    Fit a Magnaclean Pro on your return pipe to the boiler as KIAB says; this is an easy DIY job, and you can get them for less than £100. At the same time, look out for a Magnacleanse unit being sold near you (try eBay), and buy it - you will almost certainly be able to pick one up for around £250 - and you'll be able to sell it on afterwards for the same amount, or even more.

    Remove the Mag Pro unit and connect the M'cleanse to the two pipe ends. Add a couple of doses of Adey MC3+ to the cylinders and top them up with water. Open all the valves fully and run your CH system as normal.

    Check the filters on a daily basis, photograph the results and post them on here - we love dirty pictures. Wipe clean and replace. Close all the rads off (using their TRVs...) leaving only one rad fully open (both ends) each evening for a few hours - start with the 'dodgy' rad. For each individual rad, note how much sludge is removed.

    Afetr doing each individual rad, go back to them all being in use as normal (unless one rad keeps giving sludge - keep that rad running individually until the sludge has virtually disappeared.)

    Keep the machine connected for a month, even more if you still think it's collecting stuff.I had mine fitted for 2 I think - I just ignored it and left it connected. And it REALLY helped my system.

    Once you are happy your system is pretty clean - perhaps only light lemur-tail rings being formed on the magnets over a few days - remove the 'Cleanse and connect the two pipe ends to a garden hose and flush your system through - flow through up in to the boiler, and have the other end outside sitting in a bucket so's you can monitor when it's running clean. Again, shut off all the rads bar one in turn, and give each rad a couple of minutes of undivided flushing.Then flush it all.

    If you prefer, you could instead fully drain down your system - open every rad valve and also the bleed screws - starting with the highest rad. Drain fully, refill system with fresh water, run it for an hour, and drain down again...

    Refit 'Pro and add 'long term system cleaner' (I forget the code) and system inhibitor (ditto).

    Thoroughly clean the 'Cleanse, and get prepared to box it for couriering - and sell it on eBay (or locally via Gumtree and Facebook.

    Total cost - whatever the chemicals were. And the 'Pro.
    Last edited by a moderator: Oct 25, 2017
    KIAB likes this.
  8. bond007

    bond007 Member

    Hi, there wasn't much sludge in the old one tbh and i already have a Magnaclean Pro installed on the boiler. Let me try balancing 1 more time and i will take your advise if that doesn't cure the issue.

    When i changed the rad i had drained out the system fully and put an inhibitor in
    KIAB and Deleted member 33931 like this.
  9. Does your Pro collect much? Do you also have 'long-term-cleaner' in the water - a 'gentle' cleaner that can be left in permanently?

    (I have to say, after a decade of continuing problems due to low levels of sludge - which my Pro was not all collecting - the 'Cleanse did an awesome job. I noticed an immediate improvement in how my boiler behaved.)
  10. KIAB

    KIAB Well-Known Member

  11. I used Sentinel before, but - because I am Scottish and found Adey's own products to be much cheaper - I used them the last time. Every bit as effective as far as I could see.
    Dr Bodgit likes this.
  12. KIAB

    KIAB Well-Known Member

    There are a lot of nooks & crannies where crud can build up in a system, & even powerflushing won't clear.
  13. KIAB

    KIAB Well-Known Member

    Adey MC5 cleaner can only be left in for 7 day, Adey MC3 cleaner can be left in 30 days.
    Deleted member 33931 likes this.
  14. bond007

    bond007 Member

    Not checked it doe several month so will so today, also which long term cleanser do you recommend? and how do i put it in?
  15. Dr Bodgit

    Dr Bodgit Well-Known Member

    And Sentinel x800 can be left in indefinitely (good job).
  16. KIAB

    KIAB Well-Known Member

    Do find the X900 rather good, still collecting a fine covering of crud on the filter.
  17. KIAB

    KIAB Well-Known Member

    Shouldn't need to leave it in permantly, that what X900 Filter Aid is for.

    A few years ago, I did leave the X800 cleaner in my system for 5 or 6 months, due to me having appendicitis & complications.

    I still have a pot of the crud which came out of the filter, amazing radiators worked at all.
    Last edited: Oct 25, 2017
  18. Dr Bodgit

    Dr Bodgit Well-Known Member

    Indeed, shouldn't, but like you, I left mine in for quite a while until I got around to thoroughly flushing and putting the X100/900 in. I googled this topic and read that it used to have a limited time in the system but the formula changed at some point so it can now be left in.
    KIAB likes this.
  19. KIAB

    KIAB Well-Known Member

    One thing with using X800, I noticed improvements with the radiators within a hour of dosing system, & amount of crud collected in filter in first few hours was surprising.
  20. bond007

    bond007 Member

    How do i put this X800 in the radiator system?

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