X800 Longer than an hour, but how long?

[Schmill]

Ok, I've seen a few posts on this subject but none actually seem to give an answer, (so perhaps there isn't one?)

I've done some work on my heating system, and when working around the pump / vent / cold fill area I noticed the pipes had quite a nasty buildup of rust and black sludge stuck to the insides.
Last night I drained 'some' water and added X800 (so it is just plain water and X800 in there at the moment).
The X800 says that you can use it for an hour, or longer may be required for heavy buildups.
As the effected pipework is now all nicely soldered back together, how do I know when it has been in there long enough?
Niether the product, the bottle, or the website seem to give any idea of a recommended amount of time it should remain in the system.

I had it belting round the system last night with the heating thermostat set to 30 deg C, and the hot water valve set to it's manual 'open' position, with the pump at it's highest setting, but when I left this morning I set the valve and the dhw / ch thermostats back to their normal settings so as not to boil the house.
The X800 bottle does say to circulate it with all valves open, but what does it mean by that? I've opened all the TRV's fully, but should I also open up all the lockshields fully as well? (I was concerned that doing this 'might' stop the X800 circulating through the furthest rads at all?)

I'm not sure if I should be draining it out tonight, (as I had planned), as that is 24hrs rather than the single hour they 'quote', or if leaving it in longer is beneficial?
It says it includes chemicals to protect the metalwork in the system, but I don't know if this is as 'good' as the ones in the inhibitor, or if I should be aiming to get the X800 out sooner rather than later, flush, and refill with inhibitor?

Thanks

 

[Agile]

What you have done is fine.

About four hours is all it needs.

Ideally drain it out and flush until clean within 24 hours and add X100.

Tony

 

[Schmill]

Cheers Tony, will go ahead with the drain, flush, and refill tonight then

Incidently does it matter whether the system water is hot or cold when I actually drain it? I know it says to circulate it hot, but I don't know if it should be hot when I drain it too? Maybe it holds the sludge better when hot, rather than cold?!

Thanks

 

[Agile]

Makes little difference but 40 C is best.

Tony

 

[Schmill]

K, sounds good, keeps my hands warm and the hose pipe flexible without risk of burning

 

[Foobix]

Have you thought about fitting a magnetic filter?

 

[ratonnastick]

If you speak to the Sentinel the manufacturer it is now possible to leave X800 in a system with no adverse effects, this due to the fact the chemicals they now use will breakdown in about two weeks. Unlike the old stuff that had some nasty chemicals that where not acceptable in todays greener culture. x800 changed about 4 years ago from a green cap to a purple cap or x800PC. (anyone notice it doesn't fiz a much any more.)

don't forget to drain and flush if you don`t drain of flush it you have wasted your time and money.

 

[Schmill]

All done now

X800 drained out of all drained points until no more water would come out of the system. Then turned the supply back on to the FE tank and allowed the water to flow freely out of each drain off point in turn until the water was nice and clear (and ice cold!).
Then closed the points, added X100 and X200 (to try and avoid any noises due to hardwater round here!), re-filled and vented all the rads.

Hopefully sorted now, although I'm not convinced the system is correctly balanced. I took note of how many turns the lockshields were from open, and pretty much all of them were beween half a turn and a full turn from fully open, yet when I read the balancing FAQ on here it seemed to indicate that you start with all valves shut and then just crack each one open 'slightly'. Got no choice but to leave it as is for now, but will try to get hold of a temp. probe and then attempt to balance everything up properly at some point!