Platinnum combi HE air lock in central heating

[morrischilds]

I have drained out 1.5 L of nice clean fluid from the lowest pont in my central heating system with the idea of inserting 1L of Sintinel X100 into the topmost radiator. Well, all I have now is a 1.5L air bubble (somewhere) and the top radiator is still full of water! The system won't start because the boiler says the pressure is too low.

Can I re-pressurise the system and run it with that huge bubble in it in the hope that I will then get a space at the top radiator to put in the sentinel. Or will that bubble cause a problem with the pump or the burner?

Help will be appriciated - it's cold here

morris

 

[tommyl18]

fill the system back upto just over 1 bar and let it circulate and the air should find its way out either through the auto air vent or at the top of the rads then bleed them

 

[morrischilds]

Many thanks for your reply, it is all working now and I'll get a "real man" in to do it

 

[morrischilds]

Hi again, with all the radiator bleed valves closed and no leaks, when I opened the tap at the bottom point of the system it was perfectly happy to vent water because of the pressurised system. The system was still pressurised after I had vented 1.5L of water (0.7bar) so, I would guess that there was either a contracting of all pipes or a vacuum was left behind. Either way, not air.

Now it is re-pressurised all seems to be quite normal. Radiators hot top to bottom no gurgling noises etc.

morris