What do I need to know about boilers?

[Jason Barr]

I'm considering a 12-unit property that has the heat type listed as Hot Water/Steam.  I assume this is a boiler.  What is the 10,000 foot view of these type of heat systems?

Are there different types?  Obviously I'll have an expert inspect but what are you looking for as an investor when you see these systems?  

For example, I'm no residential roofing expert but if I see a lot of curling shingles or if I can tell that there's already more than 1 layer of shingles...I know I can expect to be putting $$$ into the roof soon if its curling or a larger amount of $$$ if its multiple layers.

What are the similar "tells" for Hot Water/Steam heat systems?

[Mike Sattem]

@Jason Barr,

As @Anthony Giannette mentioned, they will run forever if maintained, although the maintenance can be spendy due to the lack of qualified boiler technician (Most are plumbers with the additional certification). Most older boilers had a pump that ran at one speed, either on or off, which led to the motor burning out faster. New boilers, i.e. high efficient models, have a pump that never stops, but will actually speed up or slow down relative to the amount of heat you want put out.

I have stayed away from boilers like the plague, however I just finished rehabbing my first property with a boiler installed in 2007 and have been pleasantly surprised by it.