North American Testips 8666 Testips are used to check air/gas ratio setting of premix burners, particularly where the main burner flame is not easily visible. A Testip in the mixture line between mixer and burner can pro- vide small samples of the main flame. The flame is judged by noting its color:
Sheet 8666-1
To establish correct color more clearly, slowly increase and de- crease mixer gas adjustment. It is easiest to judge flame at about 4"wc mixture pressure. As an alternate to using color, correct ratio can be approximated by modulating gas adjustment until outer cone merges sideways with primary inner flame (do not be guided by merging of the flame at the top). An 8666 Testip capacity is 8500 Btu/hr with 4"wc mixture pres- sure. Its mixture consumption has insignificant effect on main flame in mixers 1½" air pipe size and larger. Assembly includes 4-1966-2 Pilot Tip, 1829-04 Gas Valve, and fittings.
A blue flame indicates correct air/gas ratio.
A lean flame tends to be violet.
A rich flame tends to be green.
DIMENSIONS inches
4-1966-2 Pilot Tip
pressure tap
Burner
1⁄8 pipe size
pressure tap on opposite side
5 pipe dia.
5 pipe dia.
recommended minimums
If an elbow is used in this section, allow at least 5 pipe diameters on each side of the elbow.
Allow 6" minimum fl ame clearance
1⁄8 NPT
5⁄8
4 11⁄16
8666 Testip
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