Burnham SCG manual Check limit, Adjust gas input rate to boiler

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 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.

Table 10: Gas Flow Rate in Cubic Feet

Per Hour

Seconds	Size of Gas Meter Dial
for One
	One-Half	One	Two
Revolution
	Cu. Ft.	Cu. Ft.	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

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