22
Table 9: Gas Flow Rate in Cubic Feet per Hour
4. Determine Input Rate. Multiply gas fl ow rate by gas
heating value.
5. Compare measured input rate to input rate stated on
rating plate.
a. Boiler must not be overfi red. Reduce input rate
by decreasing manifold pressure. Do not reduce
more than 0.2 inch w.c. If boiler is still overfi red,
contact your Burnham distributor or Regional
Offi ce for replacement Gas Orifi ces.
b. Increase input rate if less than 98% of rating
plate input. Increase manifold gas pressure no
more than 0.2 inch w.c. If measured input rate is
still less than 98% of rated input:
i. Remove Main Burners per procedure in
Section IX: Service.
ii. Remove gas orifi ces. Drill one (1) drill size
larger (drill size is stamped on orifi ce, or see
Key No. 4C in Section X: Repair Parts).
iii. Reinstall gas orifi ces and main burners.
Measure input rate.
6. Recheck Main Burner Flame.
7. Return other gas fi red appliances to previous
conditions of use.
N. Review User's Information Manual and system
operation with owner or operator.
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