As director of engineering for the Boston Marriott Cambridge, Robert Vass knows that each mechanical decision he makes for the hotel has 431 opportunities to fail. That’s the number of guestrooms at ...

Recently I wrote in this column that every component in a controls circuit is a power supply, a switch or a load — no other possibilities. And that means that every control, hydronic or otherwise, is ...

In a December 2014 Plumbing & Mechanical Hydronics Workshop column, we discussed the benefits of dual-fuel systems that combine a geothermal water-to-water heat pump with a mod/con boiler. The boiler ...