Great Article and Advice Harold BUT you neglected to mention as the steam cools it can and does create a vacuum and thus the air problem with no apparent leaks.
(packing glands etc)
Why would anyone try to use a hot water loop from a condensate line for heating ABOVE the boiler is always a mystery.
Think about if the installer had either put in as you suggest an indirect coil OR A tankless coil like we do for domestic hot water.
AHHHHH the joys of coming behind the unknowing huh?
