Articles by John Siegenthaler, P.E.

A hydronic system is to supply four panel radiators, each with its own thermostatic radiator valve, and an indirect water heater from a gas-fired sectional cast-iron boiler. The system is designed using primary/secondary piping.

In past columns, we’ve discussed geothermal water-to-water heat pumps and air-to-water heat pumps via hydronic heat sources. Both can be a great match to low-temperature hydronic distribution systems.

The hydronic system shown above was created to connect three gas-fired, cast-iron boilers to a low-temperature distribution system that supplies 12,000 ft. of 3/4 in. PEX tubing embedded in the floor slab.The installer spends several frustrating hours attempting to get the air out of the system. He finally gets it purged to the point that the distribution circulator is at least moving some water through the floor-heating circuits.

After completing a hydronic installation, especially one that’s taken you a few days longer than expected, do you ever ponder that there is just too much “stuff” in some of these systems?

Joe Wrenchturner gets a call to install solar water heating for a longtime customer. He buys some flat-plate collectors through an online source and decides to assemble the remainder of the system using hardware he installs for other hydronic systems.

The market for wood-gasification boilers is growing in North America. Most are used in rural areas where natural gas in not available, and thus the cost of firewood is often very competitive against the alternatives of No. 2 fuel oil or propane.

An installer is asked to provide a system that supplies two zones of fin-tube baseboard and two zones of floor heating. The system also supplies domestic water heating. He selects a mod/con boiler because it’s lighter than a conventional boiler.

Differences exist between rules of thumb and precise calculations.

 The following formula has been around the North American hydronics industry for a long time:  

 North American hydronic professionals can now choose from dozens of modulating/condensing (mod/con) boilers. Many are designed for wall-mounting. Those who design these boilers strive for small enclosures and low weight.