Burnham SCG User Manual
Page 67
 
67
Table 10: Gas Flow Rate in Cubic Feet
 
Per Hour
O.
Check limit.
1. Adjust thermostat to highest setting.
2. Observe temperature gauge. When temperature is
indicated, adjust limit to setting below observed 
temperature. Main burners and pilot burner should 
extinguish, and blower should stop.
3. Adjust limit to setting above observed temperature.
Ignition sequence should begin.
4. Adjust thermostat to lowest setting. Adjust limit to
desired setting.
P.
Adjust gas input rate to boiler.
1. Adjust thermostat to highest setting.
2. Check manifold gas pressure. See Table 5 or rating
label located in the boiler’s vestibule compartment. 
Adjust gas valve pressure regulator as necessary 
(turn adjustment screw counterclockwise to 
decrease manifold pressure, or clockwise to increase 
manifold pressure). If pressure cannot be attained, 
check gas valve inlet pressure. If less than minimum 
indicated in Table 5 or boiler’s rating label, contact 
gas supplier for assistance.
3. Clock gas meter for at least 30 seconds. Use Table
10 to determine gas fl ow rate in Cubic Feet per 
Hour.
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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 over fi red. Reduce input rate
by decreasing manifold pressure. Do not reduce 
more than 0.3 inch w.c. If boiler is still overfi red, 
contact your Burnham distributor or Regional 
Offi ce for replacement Gas Orifi ce.
b. Increase input rate if less than 98% of rating
plate input. Increase manifold gas pressure no
more than 0.3 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 
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.
Q.
Review User’s Information Manual and system
operation with owner or operator.
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