bleeding radiator problem

[zippy]

some of my radiators are airlocked and i have bought 3 radiator keys they seem to be 2 big 2 turn the bleed screw,im beginning to think sum 1 rung them a 5mm socket 2 small and a 6mm to big,any one got a solution?.Also how to do u balance radiators some of mine hot and some coldish?
thank you

 

[justlead1]

Hi Zippy. I have not come across the key not fitting the vent screw, how ever carefully unscrewing the fitting with a spanner just until you get air and water then tighten up will do the trick. As for balancing the system, the general rule is rads nearest to the boiler get better circulation than those at the system ends, due to the frictional resistance with in the system. With that in mind open all the wheel head valves fully then close lock shield valves. Select the rads you feel are closest to the boiler and open lock shield say 1.5 turns. Then select the next range in distance and open say 2 turns the remainder (assuming its a domestic system of 8 or 9 rads) open fully then monitor result and adjust accordingly. Note. thermometers clipped on to the rad flow and return and monitoring the temp. whilst adjusting the lock shield vales to achieve a temp. difference of say 10 degrees between F & R is a standard used on some commercial installations.Good Luck

 

[365drills]

Not sure about the radiator bleed key. Mine are universal but I do have recent radiators all purchased from Screwfix.

I balance mine by doing "upstairs" and "downstairs". I shut off everything upstairs completely and let them all get hot downstairs. When that happens I slowly open the upstairs ones by a crack until I feel the heat going in them.

Not sure if its the right way but my pipework has been hacked about over 40 years so its not a clean system of pipes. Oh by the way my bolier is in the loft so its hard work to get water to the bottom.