21
WHERE TO TEST (CONT.)
Furnaces (continued): Atmospheric, Gas & Oil
Atmospheric Furnace
Draft
Verify proper
• Temperature Rise
• AC side Static Pressure
Drop across coils
Verify proper combustion:
• O
2
• CO
2
• CO
• Stack Temp
• Efficiency
Natural Gas & Propane
Verify proper combustion:
• O
2
• CO
2
• CO
• Stack Temp
• Vent Pressure
• Efficiency
Test
• Limit Switch
• Pressure Switch
Set Up
• Gas Pressure
Verify proper:
• Static Duct Pressure
• Temperature Rise
• AC side Static Pressure
Drop across coils
Oil Furnace
Verify proper combustion:
• O
2
• CO
2
• CO
• Stack Temp
• Stack Draft
• Efficiency
Test & Verify:
• Smoke
Set Up
• Over Fire Draft
Verify proper
• Static Duct Pressure
• Temperature Rise
• AC side Static Pressure
Drop across coils
WHAT RESULTS ARE GENERALLY ACCEPTABLE
Atmospheric Gas
Fixed Burners
Gas Fired Burners
Oil Fired burners
(#2 Oil Fuel)
Positive Overfire Gas
& Oil
Oxygen
7 to 9% O
2
3 to 6% O
2
4 to 7% O
2
3 to 9% O
2
Stack temperature
325˚ to 500˚F
275˚ to 500˚F
325˚ to 600˚F
Draft (Water Column Inches)
-.02 to -0.4 InWC
-.02 to -0.4 InWC
-.04 to - 0.6 InWC
-.02 to -0.4 InWC
Carbon Monoxide (parts per million)
<100 ppm
<100 ppm
<100 ppm
<100 ppm
Overfire Draft (Water Column Inches)
-.02 InWC
-0.2 InWC
0.4 to 0.6 InWC
Smoke
0 (manufacturer's
recommendation)
NOTE:
Follow manufacturer guidelines for the specific equipment being serviced
Typical Excess Air Levels
O2% (measured)
Excess Air %
Natural Gas
3%
16.7%
LIGHT Oil
5%
31%
Coal
8%
62%
www.calcert.com
1.800.544.2843
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