Problem Bleeding Central Heating after Draining Down

[Lifter20]

Firstly sorry for the long post, just trying to give as much info as possible

I could do with some advice on bleeding my central heating. We bought a Bungalow last year which has been refurbished and extended. It's an oil fired Combi system driven by a Worcester Greenstar Heatslave 18/28 Boiler in the garage. The pipe runs are all in the loft using 22mm speedfit tee'd off to 10mm where the pipes run down inside the stud walls to the radiators. Over the summer I decided to fit TRV's in the bedrooms and hall. On refilling the system it was a nightmare trying to bleed all the air out... it took me ages and i ended up draining about 3ltrs of water with air in it out of the radiator furthest from the boiler before I could get water circulating around the system again.. At the top of the copper feed/return pipes from the boiler. where they go up the wall and into the loft space in the garage there looks to be auto air vents, which I can hear working when I refilled the system. The 22mm pipe run through the loft to the furthest radiator is about 24 mtrs...

Is it normally such a pain in the a*s bleeding these type of systems out?

Would I benefit from fitting another 2 auto bleed valves in the loft at the other end of the 22mm pipe run?

Cheers

Steve

 

[ringi]

Next time I drain down, I will fit drain value that will take a hose pipe next to the boiler, and then I will be able to use main water to fill the system up “bottom to top”, so as to remove the air locks between the boiler and the pump (and header tank).

Once you have air locks out of the boiler/pump pipe work, try turning off all the radiators apart from the one with the problem, then run the pump, this is likely to force out any air locks in the given pipe. (Turn up the pump if you can while doing this.)

I found that a Spirovent deaerator automatic air vent fitted in the flow from the boiler helped kept the system airlock free once I had enough water movement for the boiler to work. (I expect there is a pin hole somewhere that is letting air into a pipe, but have not be able to track it down, the system is not over pumping.)