ideal icos HE18 - how does it work? what have i done?

[hms]

I live in a three storey house and the top floor radiators have always been cool (bottom gets hot, rest of rad luke warm). Tried bleeding them to no avail. Thought the pressure was too low so I did the following:

1) turned tap (cold inlet) on and then off quickly (nothing happened)
2) turned the flicky switch thingy on the red Grundfos bit from 3 lines to 1 and then back again
3) turned the two valves on the pipe feeding into the small red tank above the cylinder 45 degrees, heard water gushing in, waited for pressure guage to go up to 1.4 then closed them

I then went downstairs and when I back to the cylinder there was water all over the floor - some kind of overflow/dump?

In meantime, my dad released some air from top floor radiators.

Now the boiler will fire up only for a few seconds and then shuts off completely. I've tried this a few times. There is a lot of noise like water and/or air moving around before it shuts off.

I know, I shouldn't have messed with it! Can anyone help?

ps - don't know if it makes any difference but the b ioler is a range tribune he and has two small tanks above it - one red and one white.
The bioler is on the ground floor and tank/cylinder on middle floor.

 

[shambolic]

Still airlocked there will be air release valves at Tribune but get someone in if you are not sure as this is an unvented cylinder !!!
The boiler is cutting off as it cant get rid of heat as airlocked

 

[hms]

progress: spoken to a gas fitter on the telephone who advises that there's an airlock and all i need to do is bleed radiators one at a time and keep topping up system so that presure is 1 bar. He says boiler is cutting out because it's overheating.

Problem now is that when i try to top up system, water pours from just below the pump and pressure falls to zero. Is this quite simply a leak?

What i don't understand then, is why the leak has only presented itself now and why my central heating was working fine on 2 storeys without apparently any pressure (it showed zero before i started messing with it???).

Any ideas?

 

[hms]

Thanks shambolic - trying to get someone out. Dare I ask, why should the fact that it's unvented worry me particularly? It's 4 years old, surely there will be a safety vavle to release excess pressure?