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Powerflushing a central heating system

Discussion in 'Personal' started by decj, Oct 12, 2019.

  1. decj

    decj New commenter

    I'm sorry...I know it's the most boring subject ever, but doesn anyone have any experience of this, please? We have three radiators which are not heating up and our plumber has suggested having them power flushed, although, he has said that it may not solve the problem. We've found a local company who want £480 to do this but I'm reluctant to pay such a large amount of money if it's not going to work. Has anyone had a central system powerflushed and has it worked...or otherwise?
    Thank you so much!
  2. magic surf bus

    magic surf bus Star commenter

    I've never had powerflushing done, but I have drained the radiators through a hosepipe into the outside drain then put some cleaning solution in the radiator circuit's header tank, prior to re-filling the circuit. Draining gets rid of some of the sludge build up, and the cleaning solution can help erode the rest to make the water flow freely again.

    That took me half a day and about £7 for the cleaning solution. A few days later I had to bleed the radiators of air, and it worked.

    I take it you've tried bleeding the radiators that aren't heating up, in case there's air trapped in them? Are they just not heating up at all, or are they hot lower down but cold higher up? Partial heating is often due to trapped air, especially in the highest up radiators in the circuit. I had to bleed the top third of our heated towel rack in the bathroom only yesterday.

    You could also check if the circuit's header tank is working properly and is actually feeding water into the system.

    Then again, maybe your plumber's tried all that.
  3. towncryer

    towncryer Lead commenter

    seems like a lot of money, Can you not just buy new radiators? I replaced 2 in my system a year or two ago and pretty sure they didn't cost that much.
    border_walker likes this.
  4. oldsomeman

    oldsomeman Star commenter

    Suprised a plumber cant undertake the power flushing as it supposed t be part of their skills,.Most power flushing is usually for the boiler, but I assume you have bled the rads first to make sure it's not an air block.
    If you want to know how then youtube is your friend. Lots of videos on there.
    border_walker likes this.
  5. FrankWolley

    FrankWolley Star commenter

    We had it done in our previous home - cost a bomb (£600+ in 2012) and quite frankly made little or no difference! I'm not sure I'd ever do it again...
  6. border_walker

    border_walker Lead commenter

    Like others I have drained and flushed ours. Did it whilst hot and circulating. For £600 I could replace the radiators.

    Sounds more likely that the plumber hadn't a clue. I assume that he did try bleeding first. Could also be the valves need replacing - even cheaper.

    But I would drain the system first. have you a header tank or a pressurised condensing boiler?
  7. FrankWolley

    FrankWolley Star commenter

    [QUOTE="border_walker, post: 12939546, member: 23601778" For £600 I could replace the radiators.


    It was a large house - 4 beds, 2 en-suite, 3 floors... Had it worked, I'd have regarded it as money well spent...but it didn't.
  8. decj

    decj New commenter

    Thank you so much for your replies. You've given me lots to think about and mull over. Much appreciated.
  9. Aquamarina1234

    Aquamarina1234 Star commenter

    Just reading this thread makes me realise how utterly helpless I would be if my husband wasn't here. I don't even understand the questions! I can and do bleed the radiators from time to time but that is the full extent of my plumbing knowledge. How did you all find this stuff out?
  10. smoothnewt

    smoothnewt Star commenter

    We had ours power flushed as the final stage of having a new boiler installed. No idea what we paid - I’d have to dig out the invoice. Certainly the rads are working a lot better than they did beforehand.
  11. Duke of York

    Duke of York Star commenter

    Power flushing a central heating system isn't something I've needed to do, but it seems to me that how successful it is, depends on how thorough the work is done. This video shows why.

    Unfortunately the plumber isn't that good at explaining what he's doing, but the key part to watch is when he checks for blockages with his thermal camera.

    After a few flushes, the camera shows there still several areas in the radiator still clogged up with sludge that more flushing is required to dislodge.

  12. colpee

    colpee Star commenter

    First thing I’d do is change the plumber ! Not only can he not sort a routine problem, but he is suggesting an expensive procedure that might do nothing?

    Removing a radiator and pumping water through it to see if it is blocked is a very simple job. If it is blocked there are a few solutions - none of them in the hundreds of pounds. If the radiators are truly knackered, replace is as easy an option.

    Before any of that though I’d be checking system pressure, correct pipe sizes, valves & header tank and pump.
    border_walker likes this.
  13. Jamvic

    Jamvic Star commenter

    Same here. Cost £500 extra. Nothing seemed much different afterwards tbh.
  14. alex_teccy

    alex_teccy Lead commenter

    I have a couple of properties in hardwater areas. So first of all your plumber may be right! But consider the variables- how old the rads are when you got your boiler etc. bear in mind that if your are in a hard water area it can destroy your boiler too- combi boilers don't like hard water at all. You should inastall a water softener if you can- having said this I've never done a power flush. But also think about your boiler first- is it okay?
    Also get a radiator key and turn the tops of the rads- if you hear a hiss they're not full.
  15. Duke of York

    Duke of York Star commenter

    The only way to be able to tell if a radiator has blockages in parts of it is to measure the temperature across each part of it. As the video I posted shows, it's a gradual process of pumping water through in each direction to clear the blockages. You can't assume that because water is flowing freely from one side to the other, it is flowing freely around the radiator. Radiators only become truly knackered if they become rusted through and leak, but whether it's cheaper to have them properly flushed through or replaced is the key question.

    I sufferred a DVT in 2016, which resulted in embolisms in my lungs. The cure for it I was given was to put me on blood thinning tablets and it seems, touch wood, to have worked. The blockages in my blood plumbing system have been flushed away, without the need to have anything replaced and turned out to be a lot less expensive than having any body parts replaced.

    Just a thought...
  16. border_walker

    border_walker Lead commenter

    I tend to use something like this after I have done anything to the system. Not convinced that any flush will remove deposits from hard water, but an acid will.
  17. Shedman

    Shedman Star commenter

    New radiators cost upwards from £30 depending on style and size. If like us you only heat one room in a house just get new radiators and fitting them should be no problem if they are the same as your old ones. Conversely, take the radiators off the wall and give them a good flush through with a hose in the garden. You only need a couple of spanners and a hose to do this. Don't forget to put inhibitor back in the system if you drain it down.
    border_walker likes this.
  18. decj

    decj New commenter

    Oh my goodness! I can't believe you've all taken the time, and trouble, to discuss such a mind-numbingly boring subject. I'm definitely erring towards trying several of your suggestions before embarking on expensive power flushing. Thank you!
    Jamvic and border_walker like this.
  19. magic surf bus

    magic surf bus Star commenter

    Hours spent fettling.

    Sometimes you're rewarded with a solution that works.
    colpee likes this.
  20. border_walker

    border_walker Lead commenter

    A lifetime of learning and a desire to do such things myself, plus save money.
    magic surf bus likes this.

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