I live on the 14th floor of a 30 story apartment building and so far, I’ve been bleeding my radiators myself.
This usually worked and after bleeding I had a fully functioning radiator, 100% filled with water.
However, last time I tried bleeding, it would only fill up to 25% of its volume, it’s like there’s no pressure in the circuit.
Am I doing something wrong?
That’s what expansion tanks are for. There shouldn’t be any air in the system itself.
Older systems have been known to use the radiators as the expansion tank. this would not meet modern code but plenty of old systems exist.