what kind of routine maintenance should be done to a boiler? how often should i drain it? whats the difference between steam heat and hot water heat?
thx
Hello Rocky…
Start here: http://www.srmi.biz/Tips.Residential_Heating_Systems.Servicing_boilers.htm
Jeff
All Boilers should be serviced annually at a minimum.
What is the question?
what are the differences between a steam boiler and a hot water boiler?
At the risk of oversimplifing, a steam boiler produces water vapor that is circulated to the areas to be heated where heat is removed, the vapor condensed and the condensate is returned to the boiler for reheating. A hot water boiler heats water to below the temperature of conversion to steam and is circulated through the building where heat is extracted as needed. In some countries “district heating” is provided as a utility to the community with hot water being circulated to all homes much like municipal water. In that case each customer is charged for the heat extracted.
i guess what im not articulating is im looking for the differences between steam and hot water systems. both systems heat water. one system citculates steam thru the house, and the other circulates hot water thru the house. one system is sealed and the other will bleed off excess pressure/air, one does not. one system operates at a higher pressure, while the other operates at about 2psi. some have one pipe, some two. one system contains a glass tube so the level of water can be monitored, one does not. i thought you all were home inspectors here 
how do i know VISUALLY which is which and what is the accompaning maintenance?
VISUALLY, steam boilers have sight glasses
Along with the sight glass on a steam boiler should be a low water cut-off float switch, which opens the circuit to the burner. Also, is a spring loaded momentary valve that should be opened once a month to flush any mud out of switch area (also known as blowing down the boiler).
Some steam boilers have a dual action float system which will add water when necessary in addition to being a low water safety.
A hot water boiler has an auto-feed pressure regulator to keep the boiler full, with no low water cut-off. So in case of relief valve failure it is inconceivable that the boiler could drain down below the aquastat/hi limit because if you take notice, the RV is always higher than the aquastat. However, the RV usually resets as the press. drops below 30 lbs.