quote:This is correct, theoretically. In practice you will find that after at least one complete heat/ cool cycle, there will be about 3 inches of air space in the pressure tank.
That is where the system adjusts itself and will maintain that level for normal operating.
I have no reason to doubt that is your experience.
However, my experience with 2511 leaves a totally full pressure tank when everything has cooled down.
2511 has a stock system, Weiand water pump, blocked-off restrictor plate and a high flow Windsor style thermostat, with the top of the radiator bleed hose running back to the pressure tank, as per TSB #8, article 61.
Larry