Commercial cast iron sectional boilers from MACNA De Dietrich allow low return water temperature of 105°F--typically 35° less than other models. This allows lower temperature operation, which yields significant savings. MACNA De Dietrich boilers feature a 30-year life, with models from 404 to 6,206 mbh, and 30% more flexibility to resist thermal shock. The boilers include an integrated boiler/chiller control system; standalone or network compatibility; real time monitoring via the Internet; offsite control, adjustment, and diagnostic; ability to correct problems via the Internet; and monitoring of return water and outdoor temperature. MACNA De Dietrich. Circle 11.