What is the basic difference between a boiler and a furnace?
- A boiler heats water; a furnace heats air
- A boiler burns oil only; a furnace burns gas only
- A boiler heats one room; a furnace heats the house
- A boiler needs no venting; a furnace needs a chimney
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A. A boiler heats water; a furnace heats air
A furnace warms air that is distributed through ducts, while a boiler heats water (or produces steam) that is piped to radiators, baseboards or radiant tubing. Either can burn gas or oil, and fuel-fired units of both kinds need venting.
Reference: Heating: system types
Which features identify a high-efficiency condensing gas furnace?
- A barometric damper and a firebrick chamber
- A draft hood and a metal single-wall vent
- A standing pilot and a clay tile chimney
- Plastic vent piping and a condensate drain line
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D. Plastic vent piping and a condensate drain line
Condensing furnaces take so much heat out of the flue gas that water condenses; the cool exhaust is carried in plastic pipe and the condensate is drained away. Draft hoods and standing pilots belong to older, low-efficiency equipment.
Reference: Heating: condensing (Category IV) furnaces
The burner flames in a natural gas furnace are yellow, lazy and wavering. What does this indicate?
- Poor combustion that may produce carbon monoxide
- A clean burner that is running at peak efficiency
- Gas pressure that is too low to be of any concern
- Normal burning when the furnace has just been started
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A. Poor combustion that may produce carbon monoxide
A properly adjusted natural gas flame is steady and mostly blue. Yellow, floating flames show poor air and fuel mixing or a dirty burner, which produces soot and carbon monoxide and calls for servicing.
Reference: Combustion: flame appearance and incomplete combustion