LG Electronics 395CAV Example, GAS Specific Gravity of Natural GAS Heat Value, Btu/Cu Ft

TABLE 6ÐMODEL 395CAV ORIFICE SIZE AND MANIFOLD PRESSURE FOR CORRECT INPUT RATE

(Tabulated Data Based on Altitude Up to 2000 Ft and 22,000 Btuh Per Burner)

GAS										SPECIFIC GRAVITY OF NATURAL GAS
HEAT		0.56			0.58			0.60			0.62			0.64			0.66			0.68			0.70			0.72
VALUE
	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld	Orf		Mnfld
(BTU/CU FT)	No.		Press.	No.		Press.	No.		Press.	No.		Press.	No.		Press.	No.		Press.	No.		Press.	No.		Press.	No.		Press.
860	41		3.2	41		3.3	41		3.4	41		3.5	41		3.7	41		3.8	39		3.4	38		3.2	38		3.3
	42		3.6	42		3.7	42		3.8	40		3.3	39		3.2	39		3.3	40		3.6	39		3.5	39		3.6
	Ð		Ð	Ð		Ð	40		3.2	Ð		Ð	40		3.4	40		3.5	Ð		Ð	40		3.7	40		3.8
875	42		3.4	41		3.2	41		3.3	41		3.4	41		3.5	41		3.6	41		3.8	39		3.3	38		3.2
	Ð		Ð	42		3.6	42		3.7	42		3.8	40		3.3	39		3.2	39		3.3	40		3.6	39		3.4
	Ð		Ð	Ð		Ð	Ð		Ð	40		3.2	Ð		Ð	40		3.4	40		3.5	Ð		Ð	40		3.7
890	42		3.3	42		3.4	41		3.2	41		3.3	41		3.4	41		3.5	41		3.6	41		3.7	41		3.8
	Ð		Ð	Ð		Ð	42		3.6	42		3.7	42		3.8	40		3.2	40		3.3	39		3.2	39		3.3
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	40		3.4	40		3.5
905	42		3.2	42		3.3	42		3.4	41		3.2	41		3.3	41		3.4	41		3.5	41		3.6	41		3.7
	Ð		Ð	Ð		Ð	Ð		Ð	42		3.6	42		3.7	42		3.8	40		3.2	40		3.3	39		3.2
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	40		3.4
920	43		3.8	42		3.2	42		3.3	42		3.4	41		3.2	41		3.3	41		3.4	41		3.5	41		3.6
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	42		3.5	42		3.7	42		3.8	40		3.2	40		3.3
935	43		3.7	43		3.8	42		3.2	42		3.3	42		3.4	41		3.2	41		3.3	41		3.4	41		3.5
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	42		3.5	42		3.7	42		3.8	40		3.2
950	43		3.6	43		3.7	43		3.8	42		3.2	42		3.3	42		3.4	41		3.2	41		3.3	41		3.4
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	42		3.5	42		3.6	42		3.7
965	43		3.4	43		3.6	43		3.7	43		3.8	42		3.2	42		3.3	42		3.4	41		3.2	41		3.3
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	42		3.5	42		3.6
980	44		3.8	42		3.5	43		3.6	43		3.7	43		3.8	42		3.2	42		3.3	42		3.4	41		3.2
	43		3.3	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	42		3.5
995	44		3.7	44		3.8	43		3.5	43		3.6	43		3.7	43		3.8	42		3.2	42		3.3	42		3.4
	43		3.2	43		3.4	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð
1010	44		3.6	44		3.7	44		3.8	43		3.5	43		3.6	43		3.7	43		3.8	42		3.2	42		3.3
	Ð		Ð	43		3.3	43		3.4	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð
1025	44		3.5	44		3.6	44		3.7	43		3.4	43		3.5	43		3.6	43		3.7	43		3.8	43		3.2
	Ð		Ð	43		3.2	43		3.3	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð
1040	44		3.4	44		3.5	44		3.6	44		3.7	43		3.4	43		3.5	43		3.6	43		3.7	43		3.8
	Ð		Ð	Ð		Ð	43		3.2	43		3.3	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð
1055	44		3.3	44		3.4	44		3.5	44		3.6	44		3.8	43		3.4	43		3.5	43		3.6	43		3.7
	Ð		Ð	Ð		Ð	Ð		Ð	43		3.2	43		3.3	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð
1070	44		3.2	44		3.3	44		3.4	44		3.5	44		3.7	44		3.8	43		3.4	43		3.5	43		3.6
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	43		3.2	43		3.3	Ð		Ð	Ð		Ð	Ð		Ð
1085	45		3.8	44		3.2	44		3.3	44		3.4	44		3.6	44		3.7	44		3.8	43		3.4	43		3.5
	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	43		2.3	43		3.3	Ð		Ð	Ð		Ð
1100	45		3.7	45		3.8	44		3.2	44		3.4	44		3.5	44		3.6	44		3.7	44		3.8	43		3.4
	Ð		Ð	Ð		3.4	Ð		Ð	Ð		Ð	Ð		Ð	Ð		Ð	43		3.2	43		3.3	Ð		Ð

b. Check gas input rate by clocking gas meter.

(1.) Obtain average yearly heat value for local gas supply.

(2.) Check and verify orifice size in furnace. NEVER ASSUME THE ORIFICE SIZE. ALWAYS CHECK AND VERIFY.

CAUTION: DO NOT redrill burner orifices. Improper drilling (burrs, out of round, etc.) can cause excessive burner operating noise and misdirection of burner flames. This could result in flame impingement on burners and heat exchanger surfaces, leading to potential failures.

(3.) Turn off all other gas appliances and pilots.

(4.) Start furnace and let run for 3 minutes.

(5.) Measure time (in sec) for gas meter to complete 1 revolution.

(6.) Refer to Table 7 for cu ft of gas per hr.

(7.) Multiply gas rate (cu ft/hr) by heating value (Btu/cu ft).

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EXAMPLE:

Btu heating input = Btu/cu ft X cu ft/hr

Heating value of gas = 1070 Btu/cu ft

Time for 1 revolution of 2 cu ft dial = 72 sec

Gas rate = 100 X 1070 = 107,000 Btuh

(8.) Measured gas input should not exceed gas input on unit rating plate.

(9.) Proceed to item c to adjust manifold pressure.

c. Adjust gas input.

(1.) Remove regulator adjustment seal cap. (See Fig.

12.)

(2.) Turn adjusting screw counterclockwise to decrease input. Turn screw clockwise to increase input. DO NOT set manifold pressure less than 3.2-in. wc or more than 3.8-in. wc for natural gas. Make any major adjustments by changing main burner ori- fices.