Page 76 - Boiler plant and distribution system optimization manual
P. 76
Combustion Analysis 61
Figure 7.2—Smoke spot testing procedure.
Figure 7.3—Smoke spot rating scale.
1. Soot deposits on heat exchange surfaces. LOW STACK TEMPERATURE
2. Short circuits of hot combustion gases due to If the stack temperature drops lower than
problems with baffles. normal, lower than 250 F for natural gas or 275-
3. Over firing, check fuel rate. 300 F for oil.
4. Water side scale deposits from improper wa-
1. Possible under firing.
ter treatment.
2. Incomplete combustion of gas with danger-
5. High excess air which reduces combustion
ous carbon monoxide production.
chamber heat transfer.
