i cannot get thru a full shower without the water turning cold
so it sounds like your steam boiler has a tankless hot water coil in it much like mine does. there's a couple things that could be going on. 1. the water level in your boiler may not be to the top of your coil. there is usually a watchglass tube that tells you your water level, and the auto fill unit usually dosn't fill it as far as it needs to work your hot water right. so see if the water level is at the same point as the hot water out pipe. 2. the boiler runs off a air temperature thermostat, and to make sure the hot water is hot all the time, it has a internal water thermostat for that. this thermostat usually has a coper capillary tube that goes into a hole at your tankless coil, and then has it's own temp settings, and will also turn the boiler on (but turn it off before it gets to a steam temperature) so check that thermostat.
