In heating systems using boilers for radiant floor or baseboard heat, and in which the piping is a closed system using something other than water, what fluids are commonly used?
Does anyone have good, high-resolution, cutaway graphics of these systems?
The residential market usually installs good old municipality treated tap H2O, plain and simple. There are cases in freezing climates where techs will install an approved anti-freeze, especially when retired folks spend their winters down south and aren’t around to call a serviceman when things go amiss. This keeps the pipes from freezing.
If there are any power engineers on board who care for large commercial/industrial boiles, they will be able to tell about all tests done regularly (some daily, I believe) and the additives (anti-corrosives, PH balancing,etc) they may adjust the heating water with.
See: http://www.accepta.com/water_treatment_chemicals/boiler-water-treatment.asp
More information here that might help.
http://www.engineeringtoolbox.com/ethylene-propylene-glycol-d_904.html
Marcel 