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Method of Test for Tracer Gas Test of an Outdoor Furnace Designed for Installation Without a Flue Pipe.


pdf icon Method of Test for Tracer Gas Test of an Outdoor Furnace Designed for Installation Without a Flue Pipe. (2062 K)
Liu, S. T.; Kelly, G. E.

NISTIR 6257; 20 p. November 1998.

Available from:

National Technical Information Service

Keywords:

furnaces; flues; pipes; annual fuel utilization; ANSI/ASHRAE Standard 103; DOE test procedure; efficiency; flue gas measuring location; flue pipe; gas-fired furnace; induced draft furnace; outdoor installation; power burner draft factor; tracer gas test

Abstract:

An induced draft, gas-fired furnace originally designed for outdoor installation without a flue pipe was tested by the tracer gas method to determine its off-cycle power burner draft factor. When conducting the tracer gas test, the lack of the needed space for sensor installations and for shielding the sensors from ambient air disturbance creates an accuracy problem for the manufacturers and the testing agency to properly conduct the test. This report is to determine the feasibility of attaching a short flue pipe to the outdoor furnace during the optional tracer gas test to facilitate test measurement without significantly increasing the measured power burner draft factor due to the stack action of the added flue pipe. The results showed that it is possible to conduct the tracer gas test with a short flue pipe of less than 0.3 m (12 in.) without changing the calculated results for the value of Annual Fuel Utilization Efficiency (AFUE). Therefore, it is recommended that a short flue pipe, between 0.2 to 0.3 m (8 in. to 12 in) in length, be allowed in the Department of Energy (DOE) furnace test procedure during the optional tracer gas test for an outdoor furnace designed for installation without a flue pipe.