Steveb1964, it seems from what I've seen - though others will disagree:
All older systems have SOME grot in them.
Some are remarkably cleaner than others. Probably due to combination of good design, correct flux, cleaning filling and emptying after installation, good quality inhibitor use and replenishment. But it's very rare to have the installation info available in that much detail to do really objective comparisons.
I have often shoved the mains through a system before doing anything else. That does give a good idea of how dirty the system is, very quickly. Sometimes it all comes out clean within 20 minutes, with just a couple of minutes per rad. Then you have to look at your powerflusher and wonder how much any further effort is going to yield. SOmetimes half an hour per rad isn't enough though - bash the rad and more dirt comes out every time.
It IS worthwhile making sure the rad isn't being bypassed by the boiler or HW cylinder, which may mean adding a couple of extra valves. SOmetimes you can just shut a pump valve or rely on S plan 2 ports to be shut. You cannot flush through a drain cock! Also rad valves aren't very good, and trv's are the worst - holes can be tiny.
Power flushing/ chemical flushing aren't mutually exclusive - you use chems in powerflushing!. We've all come across systems which had sludge in where putting chems in, running for a week or two, followed by emptying and refilling, leaves all the downstairs radiators not working! For those Fernox DS40 or Kamco FX-2 are your only hope, without mains or power flushing.
Given the chance we'd all love to run a system with chems for a week or four before power flushing, but if that isn't possible you have to use chems designed for a 1 day Pflush. X400 takes longer than they say - like 4-6 weeks. Otherwise dirty sytems will not come clean.
Reversing, easier with a machine, does lift the sludge well. I've seen a demo with a perspex "rad" which was impressive.
Mains is useful for shifting the mobile grot out, Powerflushing is better for circulating chems to act on stuff which won't come straight out.
Getting the rads outside, inverting them when 1/3rd full for 5-10 minutes, until the water comes out clear despite whacking them, appeals to me. Flow from end to end can bypass grot, but inverting does at least try to shift it.
Systems which have always been sealed tend to be far cleaner than old ones which have been open. I've never seen a sealed system be very dirty, though I daresay others have. COmbis clog up on a whim though.
Remember Fernox claim you can get "up to 80%" of dirt out of a system. 20% of what some old systems have in them would kipper a combi in no time at all. If you're changing an old cast iron lump of a boiler in an open system to a new combi, and the rads are 30 odd years old, replacing them isn't a bad idea.
All older systems have SOME grot in them.
Some are remarkably cleaner than others. Probably due to combination of good design, correct flux, cleaning filling and emptying after installation, good quality inhibitor use and replenishment. But it's very rare to have the installation info available in that much detail to do really objective comparisons.
I have often shoved the mains through a system before doing anything else. That does give a good idea of how dirty the system is, very quickly. Sometimes it all comes out clean within 20 minutes, with just a couple of minutes per rad. Then you have to look at your powerflusher and wonder how much any further effort is going to yield. SOmetimes half an hour per rad isn't enough though - bash the rad and more dirt comes out every time.
It IS worthwhile making sure the rad isn't being bypassed by the boiler or HW cylinder, which may mean adding a couple of extra valves. SOmetimes you can just shut a pump valve or rely on S plan 2 ports to be shut. You cannot flush through a drain cock! Also rad valves aren't very good, and trv's are the worst - holes can be tiny.
Power flushing/ chemical flushing aren't mutually exclusive - you use chems in powerflushing!. We've all come across systems which had sludge in where putting chems in, running for a week or two, followed by emptying and refilling, leaves all the downstairs radiators not working! For those Fernox DS40 or Kamco FX-2 are your only hope, without mains or power flushing.
Given the chance we'd all love to run a system with chems for a week or four before power flushing, but if that isn't possible you have to use chems designed for a 1 day Pflush. X400 takes longer than they say - like 4-6 weeks. Otherwise dirty sytems will not come clean.
Reversing, easier with a machine, does lift the sludge well. I've seen a demo with a perspex "rad" which was impressive.
Mains is useful for shifting the mobile grot out, Powerflushing is better for circulating chems to act on stuff which won't come straight out.
Getting the rads outside, inverting them when 1/3rd full for 5-10 minutes, until the water comes out clear despite whacking them, appeals to me. Flow from end to end can bypass grot, but inverting does at least try to shift it.
Systems which have always been sealed tend to be far cleaner than old ones which have been open. I've never seen a sealed system be very dirty, though I daresay others have. COmbis clog up on a whim though.
Remember Fernox claim you can get "up to 80%" of dirt out of a system. 20% of what some old systems have in them would kipper a combi in no time at all. If you're changing an old cast iron lump of a boiler in an open system to a new combi, and the rads are 30 odd years old, replacing them isn't a bad idea.
you should see his mate...UIOPA.even worser
