Burnham SCG, Installation & Service Instructions Manual

Page: 70 / 96

70
TABlE 1: 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
13 to determine gas flow rate in Cubic Feet per
Hour.
WARNING
Failure to properly adjust gas input rate will result
in over firing or under firing of the appliance.
Improper and unsafe boiler operation may result.
4. Determine Input Rate. Multiply gas flow rate by gas
heating value.
5. Compare measured input rate to input rate stated on
rating plate.
a. Boiler must not be over fired. Reduce input rate
by decreasing manifold pressure. Do not reduce
more than 0.3 inch w.c. If boiler is still overfired,
contact your Burnham distributor or Regional
Office for replacement Gas Orifice.
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 orifices. Drill one (1) drill size
larger (drill size is stamped on orifice, or see
Section X: Repair Parts).
iii.
Reinstall gas orifices and main burners.
Measure input rate.
6. Recheck Main Burner Flame.
7. Return other gas-fired appliances to previous
conditions of use.
Q.
Review User’s Information Manual and system
operation with owner or operator.
Seconds
for One
Revolution
Size of Gas Meter Dial
One-Half
Cu. Ft.
One
Cu. Ft.
Two
Cu. Ft.
30 60 120 240
32 56 113 225
34 53 106 212
36 50 100 200
38 47 95 189
40 45 90 180
42 43 86 172
44 41 82 164
46 39 78 157
48 37 75 150
50 36 72 144
52 35 69 138
54 33 67 133
56 32 64 129
58 31 62 124
60 30 60 120