My central heating system is prone to air in the radiators. They require bleeding at last weekly to keep them operating properly.
The system runs off a Stanley 80,000 B.T.U. gas cooker/water heater/central heating unit.
So far, a leak has not been detected, and the problem has been plagueing me over 3years at least

porgypie, September 2008

It could be Hydrogen forming in the system due to the wrong types of metals being in contact with each other and water.
Has anybody been below the floors to check the pipework for leaks,especially at manifolds?This is the most likely cause.Get someone to go below decks and check every pipe connection and areas of the ground for dampness..Best to do it when the system is cold.
3 years is a long time to have a problem like this

Gasman, September 2008