i have 6 rads
as it,s well into the 70,s outside i think this is the time to flush and change my central heating water so question is....do i turn the mains tap off
and drain via a rad then put some new antifreeze in the tank,if so,how much antifreeze do i need and how often should it be changed ?.
i have 6 rads
Not so much 'antifreeze' but, as your title suggests, corrosion inhibitor. It wouldn't hurt to do it frequently like once a year but
otherwise you can test for the correct concentration and add as required. Most of these products seem to recommend about a litre of inhibitor for 10
radiators.
Pretty much as you said. Drain some or all of the water out (with the water supply off, or the CH tank ballcock tied up) and add the stuff to the
header tank. If you want to flush the system, which is not a bad idea, run it for a while with some CH cleaner in the system then drain again.
There should be a proper drain point somewhere. Depending on the layout you may need to drain from all the low points - this is often the case if the
pipework runs in the ceiling and you have loops coming down to ground floor radiators - there should be a drain point at the low point in each loop.
If you really want to go to town you could take all the rads off and flush them outside.
Definitely worth doing, and if you are uncertain, use a cleanser first. Downside is it needs the heating to be on to work!
If you think there is a lot of crap in the system, consider a magnaclean or similar. Particularly if you have a combi. I fitted one to an 8 year old
system, and it collected loads of stuff over a few months. In fact it was almost full after a day 
. But I think that system had been left without
inhibitor since installation despite being told otherwise.
Be very very careful when doing this. My mate just did this and he put his finger over a pipe to stop the black gunk central heating water coming
out. Unbeknown to him he had a little cut on his finger. Some of the stuff got into his finger/bloodstream. 6 hours later he was in A&E being
pumped full of antibiotics, 12 hours later the infection had run up his arm. I could see red stripes running from his finger across his hand and up
his forearm. He went back to A&E and they operated taking the tip of.
In all he spent 6 nights in hospital and lost his finger up to the first knuckle. This is not a story that happened to a mate of a mate of a mate.
It was a very good friend of mine and I can provide pictures if required. Doctors said 20 years ago he'd have lost his arm, 50 years ago
he'd have lost his life. The
Wear some gloves!!!!!
[Edited on 12/5/15 by Irony]
Thanks guys and Irony,just goes to show even the simple jobs can cause nasty problems,didnt even think about that sort of thing.
quote:
Some of the stuff got into his finger/bloodstream.
If you start disturbing things beyond a basic drain then you may want to power flush, you hire them.
It will remove loads of rubbish, beware if you have a combi boiler it's may send all the crap to the heat exchanger so you need to get the
direction right.
had a quick sample drain from the rads,nice and clean with a slightly oily feeling so i will just drain the tank and refill with the inhibitor.
thanks for your help guys
quote:
Originally posted by whitestu
quote:
Some of the stuff got into his finger/bloodstream.
Do you mean some of the inhibitor or was it just dirty water?
Stu
Slightly OT but how long should radiators last before they rust threw and leak?
Our house is 15years old and one has just sprung a small leak,which looks to be caused by rusting threw 
quote:
Originally posted by CosKev3
Slightly OT but how long should radiators last before they rust threw and leak?
Our house is 15years old and one has just sprung a small leak,which looks to be caused by rusting threw
There is air dissolved in the water.
quote:
Originally posted by Slimy38
quote:
Originally posted by CosKev3
Slightly OT but how long should radiators last before they rust threw and leak?
Our house is 15years old and one has just sprung a small leak,which looks to be caused by rusting threw
I thought rust requires air as well as water? So I wouldn't expect a radiator (in normal use) to rust from inside?
My parents had one leak after 2 years. The rad company sent a new one, warranty didn't cover fitting........(took me an hour of faff, tea and
biscuits, chunky M+S ones IIRC)
It may just be the one that is iffy, but it may be they are all on their way out. So, replace just the one, or all?? If you can get the same size and
make, hopefully it is just shut the valves off and swap, hopefully the brackets don't need changing. Fingers crossed.
Dissolved air is forced out of water as the temperature approaches boiling point so getting the system properly hot and bleeding the system should reduce the amount of 02 in the system and reduce corrosion. A system and that has leaks and is continuously topping up will corrode faster.
quote:
Originally posted by cliftyhanger
My parents had one leak after 2 years. The rad company sent a new one, warranty didn't cover fitting........(took me an hour of faff, tea and biscuits, chunky M+S ones IIRC)
It may just be the one that is iffy, but it may be they are all on their way out. So, replace just the one, or all?? If you can get the same size and make, hopefully it is just shut the valves off and swap, hopefully the brackets don't need changing. Fingers crossed.
quote:
Originally posted by Slimy38
I thought rust requires air as well as water? So I wouldn't expect a radiator (in normal use) to rust from inside?