We have a somewhat temperamental 1960's heating system that occasionally requires attention to let out some air or add some water.
The pressure in the heating system was very low and it has been making a lot of noise since we turned it back on so I knew it was time let out the air and put in some water...
Letting out the old water was no problem, but then I have to connect a hose to the bottom of the boiler and fill it up thus increasing the water pressure to that of the mains (quite high as it happens - approximately 3 bar). Then I have to take off the hose and put on a cap.
Well it should be as there is a tap on the boiler to stop the water coming out, but this has apparently not worked for about 30 years.
The answer I found is to leave the tap to the hose on full blast whilst unscrewing the end attached to the boiler as fast as you can and then screw on the cap as fast as you can so that the pressure in the boiler doesn't drop too much.
The result:Getting soaked in cold smelly water.