Single Pass Boilers Vs. Triple Pass Boilers

Older, single-pass style boilers run at 500 degrees and run in a single-pass.  This means that combustion gases travel the length of the boiler, resulting in an unnecessary loss of heat. New boilers, like the Buderus Boilers, run at 300-350 degrees and pass through 3 “chambers” to efficiently use heat.  A 3-pass boiler design is the most efficient way to get the maximum amount of heat from the fuel.  The design extracts heat from three times as much interior surface area of the boiler, compared to a single-pass, “pin-type” boiler design.

Buderus boilers provided this great example illustrating the efficiency of 3-pass boilers:

If you were heating water for a cup of tea, would you use a pasta pot or a teapot? Think of the typical, large-mass, single pass boiler as a pasta pot (boilers typically hold 15-17 gallons of water) and a low-mass, 3-pass boiler as a teapot. European systems in today’s houses only hold 5-8 gallons of water. Why burn all the fuel necessary to heat 17 gals. of boiler water in a 600lb., single pass boiler? A low-mass European boiler with it’s 3-pass design and 4 gals. of water content will satisfy the call for heat before the single pass boiler has even warmed up. The single pass boiler has heated twice the amount of iron and four times the amount of water.  All that excess heat goes “up the chimney” with your fuel dollars.

We would be happy to discuss upgrading your boiler system to a three-pass design.  Call 860-354-8242 today!