Hello,
I will be draining down the CH to remove a couple of radiators so that I can decorate behind them and I will probably change a couple at the same time. Is it safe to leave the CH without water in? I'm worried that having air inside the radiators may encourage rust? How long can I leave them empty before I refill (with inhibitor)?
Thanks.
You don't have to drain the entire system to remove / change a radiator. If it's a conventional unpressurised system, tie up the ball c*ck in the expansion tank, put a rubber tapered plug in the tank outlet from inside and the expansion pipe (even a carrot will do!), and with a washing up bowl under one lockshield valve, and with both rad valves firmly shut, undo the valve to rad nut and let the water drain into the bowl.
(Even simpler now I have a pipe freezer - freeze both pipes solid and then do your damndest !)
AWEM
On Sat, 12 May 2007 09:23:32 +0100, "Andrew Mawson" mused:
You don't need to tie up the valve in the header etc... if you're just removing a radiator. You would only need to do that if you're removing valves and pipework as well.
The OP just needs to close the valves, drain the radiator off and then can turn the heating back on and the rest of the system will still work. Even if you drain it all down it's not going to rust and roit and fall to pieces within a few days. I wish had such trivial things to unneccesarily worry about!
worried
removing
Like most things Stuart, it is a worry to those who haven't done it before. The ball c*ck tie up is a safety precaution when things go wrong
AWEM
On Sat, 12 May 2007 10:43:34 +0100, "Andrew Mawson" mused:
I'd rather have all the heating on though rather than leaving the whole lot off while you decorate.
Thanks for the replies. As you guessed, I have not done it before. I'm wanting to strip paper behind a couple of radiators and tile behind another and upgrade two small single rads. to double ones, so rather than drain down several rads, it makes sense to drain the whole lot (or so I thought). Also I don't know what inhibitor the previous people had, so it's a good time to drain and replace the inhibitor.
Depending on how tight the pipes are, you may find that you can just lift a rad off its crutches, and loosening the end nuts a little, tilt it forward, while you decorate.
As our tanks are difficult to get at - having been installed without a thought to any maintenance being needed ( mains supply valve behind the bath for example!) - I put a couple of thumb lever type gas taps (few people seem to stock such simple devices dedicated for water) in the ball valve lines to both main water tank and header tank - makes servicing things much easier. Having found how handy this was, I also put one in instead of the standard drain down valve, which I find tends to leak after the seal is damaged as it is opened.
(Whilst on the subject, there used to be a handy isolator valve with a simple thumb press action. I fitted one to a toilet cistern, and found it v clever and effective, but I've never seen one on sale since...)
S
Is it a vented system with a header tank or a sealed system? If the former I would be less inclined to drain down without good reason since you may find you have a system that is difficult to refill.
No need to drain, just add new inhibitor. If it has not been done in recent memory then it is probably due a dose. You won't over inhibit as such.
It has a header tank; why would this be tricky to refill?
I wasn't sure if different brands of inhibitor would be compatible?
I was just concerned that am my pace, the rads. might be empty for a week or so and was worried about this causing rust.
Thanks.
On Sun, 13 May 2007 09:09:36 GMT, snipped-for-privacy@nospam.org mused:
Airlocks.
No, a week would be fine. I thought you were expecting they would be empty for a long time.
If I bleed all the radiators, won't this be fine?
How long is too long? If I work slowly and encounter problems along the way would I be all right if they were empty for two or three weeks or a month?
Thanks.
More likely to be a problem is catching all the evil black sludge that will drip everywhere when you start heaving the rads about and/or cutting pipes (don't drop any on the carpet - even 'empty' rads - can make a right mess) Have some suitable bungs/corks handy: you might want them in a hurry: don't carry an unbunged rad through a nicely carpeted house on your way to flushing it out with the hose in the garden.
Depending on how intricate your pipework is, once the whole system is 'drained down', there will usually be lots of sections that did not drain and are waiting to gush forth once you start disturbing things. The same is true for air locks when you go to fill it all up again. You have to go round feeling all the rads, with both valves open and the pump on full, bleeding any that don't get warm, and periodically also bleeding the pump and any stack bleed valves there may be at high points in the system. Once all the rads are warm and thus getting circulated, then you start nipping up one end valve of each, as the balance valve, until all the rads are the same temp (ish is good enough!). Next, turn down the pump to the minimum that will keep all the rads warm. Then the individual rads can be set, with the normal regulating valves, to whatever is best for each room.
There are other things that can cause uneven warming (diverter valve that shares the boiler circuit between CH and hot water, can get stuck for example), but you can ask again if normal measures at balancing don't seem to work.
Be prepared to have to sort out the odd drip/leak - have PTFE tape, proper spanners, spare olives etc. to hand. An assortment of Speedifit bits and pieces is handy too.
Have fun!
S
On Mon, 14 May 2007 08:48:01 GMT, snipped-for-privacy@nospam.org mused:
Possibly. You'll find out when you come to do it, it'll either work or it won't. ;)
How long does it take something to rust to an unusable state if left to dry out naturally and then left in a house? Have all your saucepans rusted through yet after leaving them on the draining board then sticking them in a cupboard?
I hadn't thought of that. So even if I work at a snails pace, I should have nothing to worry about. I'm not intending to work that slow but I figured I should allow extra time because there's always an unseen hurdle, isn't there? Thanks for the reassurance.
Hello,
It's my first time doing this, as you may have gathered.
Does a flush with sludge remover beforehand help remove the sludge?
From what you say I should give it a thorough rinse with a hose to remove the sludge completely?
Thanks.
I've never tried that either, but, I would guess that: if your system is normally only run for part of the year; and the pump is on a low setting (as it should be if poss for minimum energy use and noise), then sludge is more likely to accumulate in slack points than if all was at full speed and constantly being stirred up. If this is the case, then I would imagine that a flushing compound run at high speed might help loosening things up. I expect though, that even if you leave the top up ball valve open while you drain and circulate at the same time until the water comes out clear, you will still find that when you tip up a rad, some sludge will come out.
If you do take a rad off completely a good idea is to have some end caps to temporarily blank off the pipes when you do this eg.
I once took rads off completely to make it easy to flush them with the hose in the garden and then rub down and repaint them (they had been badly 'decorated' in the past). Having done this (and tried refurbishing all the valves too!), I can safely say this was a waste of time and effort (rubbing down is a nightmare!) as new rads and valves are frighteningly cheap - unless you want odd shapes and sizes - and indeed, even replacing washers can be more expensive than buying a new valve (you can get them by the bagful at Wickes for eg., or Screwfix will deliver them to your door - with the odd c*ck up...). Similarly, I used to try and clean out copper pipes and reuse them, but now we have plastic pipe on a reel, and speedfit fittings that literally just push together, I really would not bother with copper any more.
But as I noted earlier, if your rads are not leaking, are working well in heating the house the way you like it, and all you want to do is decorate behind them, then the first thing I would try is just to loosen the pipe connections slightly and lift the rad off its crutches and rotate it forward - taking its weight on a chair or similar while you decorate behind it. A flush would probably make this less likely to drip any black drops - but on the other hand, the flushing compound might reactivate any old weeping points there might be. Similarly, remember that a pipe has two ends, and when you pull one rad, you may be pulling the pipe out of another! Always check and check again for leaks, whenever you make any changes to plumbing.
Flushing is, nevertheless, a good idea, whatever you choose to do in the end, and then you should include an antiknock/anticorrosion product when you fill back up (making sure you have done up the drain c*ck first - the stuff is silly expensive!).
One last thought: if your system has seemed rather slow to warm up, you may find that the pump impeller vanes are blocked. This is only held in with four allen screws, and is a lot cheaper to clean out than replace - though do not be tempted to abuse the spindle as it is ceramic and brittle.
All in all, a messy job, but v nice to sit back and enjoy when it is all running smoothly again. (With the 'Speedfit' plastic stuff (you can also get push on metal fittings too - no need to set fire to the house with blowlamps!), its almost a much fun as leggo!)
Have fun,
S
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