how do i flush my heating?

5 May 2008
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United Kingdom
i had a engineer out to day and he said my central heating systems need flushing .
i have got some sentinel x300 universal cleanser, witch say to use 1% of system volume i,e 1liter per 100 liter of system water. but how do i no how much is in my system .
i have a britony combi se 80 with 7 rads.
and when i no the volume how do i flush a system
i have sentinel x100 inhibitor to place in after the flushing to stop the slug and crap building back up.
can anybody help.
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You need X800 not X300 which is only for cleaning new systems!

My system is a bit bigger than yours, and has a hot-water cylinder and F&E tank, it contains 20 gallons (measured) which is a bit less than 100 litres.

So yours is going to be rather less. But i would cheerfully use a litre of chemical if I were you.

If you have reason to believe it contains black sludge, and you can do simple plumbing, and can afford an extra £100, you could fit a Magnaclean which is very rewarding as it traps circulating black sediment which you can empty out from time to time, it prevents it being able to build up into new blockages.

I am just a householder.

You will find more information in the first few threads on

"Please see if the answer to your query is already covered by the Wiki"
agile i looked at the x800 and it heavy duty clean for cleaner machines,
so i think i go with the x400 as x300 is for new systems.
but thanks anyway m8 ;)
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but how do i put it in the system? :oops:

p.s thanks john that help me so a liter will be ok.;)
inject it through a bleed vent plug. You will find a kit to do this in the place that sells the chemical. You have to buy the concentrate in a sort of cylinder, not the liquid in a plastic bottle.

If you use X400 and the system is dirty you will find the water goes deep black very quickly, as it loosens black sediment. You can leave it in for 4 weeks to loosen as much as you can so you can flush it out.

It is possible to use the liquid, but you have to partially drain and fiddle about with a funnel and hose to get it in.

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