Installer’s Guide
T AUTOMATIC GAS VALVE |
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| MAIN MANUAL | GROUND UNION JOINT | ||||
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| SHUTOFF VALVE | ||||||
WITH MANUAL SHUTOFF |
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| DRIP |
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| LEG |
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MAIN MANUAL
SHUTOFF VALVE
GROUND |
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UNION JOINT |
| LEG | AUTOMATIC GAS VALVE |
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| WITH MANUAL SHUTOFF |
HORIZONTAL FURNACE GAS PIPING MAY BE FROM EITHER SIDE (UPFLOW SHOWN)
TABLE 13
NATURAL GAS ONLY
TABLE OF CUBIC FEET PER HOUR OF GAS
FOR VARIOUS PIPE SIZES AND LENGTHS
PIPE |
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SIZE | 10 | 20 | 30 | 40 | 50 | 60 | 70 |
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1/2 | 132 | 92 | 73 | 63 | 56 | 50 | 46 |
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3/4 | 278 | 190 | 152 | 130 | 115 | 105 | 96 |
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1 | 520 | 350 | 285 | 245 | 215 | 195 | 180 |
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1050 | 730 | 590 | 520 | 440 | 400 | 370 | |
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This table is based on pressure drop of 0.3 inch W.C. and 0.6 SP.GR. gas
TABLE 14
ORIFICE SIZES
INPUT | NUMBER | MAIN BURNER ORIFICE | |
RATING | OF | DRILL SIZE | |
BTUH | BURNERS | NAT. GAS | LP GAS |
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40,000 | 2 | 45 | 56 |
60,000 | 3 | 45 | 56 |
80,000 | 4 | 45 | 56 |
100,000 | 5 | 45 | 56 |
120,000 | 6 | 45 | 56 |
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COMBUSTION AND INPUT CHECK
1.Make sure all gas appliances are off except the fur- nace.
2.Clock the gas meter with the furnace operating (de- termine the dial rating of the meter) for one revolu- tion.
3.Match the “Sec” column in the gas flow (in cfh) Table 16 with the time clocked.
4.Read the “Flow” column opposite the number of sec- onds clocked.
5.Use the following factors if necessary: For 1 Cu. Ft. Dial Gas Flow CFH =
Chart Flow Reading ÷2
For 1/2 Cu Ft. Dial Gas Flow CFH =
Chart Flow Reading ÷4
For 5 Cu. Ft. Dial Gas Flow CFH =
10X Chart Flow Reading ÷4
6.Multiply the final figure by the heating value of the gas obtained from the utility company and compare to the nameplate rating. This must not exceed the nameplate rating.
7.Changes can be made by adjusting the manifold pressure or changing orifices (orifice change may not always be required). To adjust the manifold pressure:
a. Turn off all electrical power to the system. b.Attach a manifold pressure gauge to the outlet
pressure tap marked "OUT PRESS TAP" on
c. Turn on system power and energize valve. d.Remove the regulator adjustment screw cap on
the gas valve for manifold pressure adjustment. e.Turn the adjustment nut clockwise to increase the gas flow rate, and counterclockwise to de- crease the gas flow rate using a 3/32" hex wench.
f. The final manifold pressure setting shall be as specified in Table 15 with an input of no more than nameplate rating and no less than 93% of the nameplate rating, unless the unit is derated for high altitude.
g. Replace the regulator adjustment screw cap and tighten securely.
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