Évaluations - 2, GPA: 3.5
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Facilité d'utilisation
When lighting the furnace for the first time, however, perform the following additional steps: 1. If gas supply was not purged before connecting furnace, line will be full of air. Loosen ground joint union and allow supply line to purge until gas odor is detected. Never purge gas lines into a combustion chamber. Immediately upon detection of gas odor, retighten union. After 5 minutes, light furnace in accordance with instructions on furnace rating plate. 2. Main burners should light 25 to 75 seconds after pilot. If main burners do not light within prescribed time period, check pilot flame. 3. The pilot flame should be soft blue in color and it must provide good impingement on the pilot switching element. The flame should extend above the burner carryover port to provide a proper burner ignition. When the pilot flame requires adjustment: a. Locate adjustment screw marked “PILOT ADJ” on top of gas valve. b. Remove cap and turn adjustment screw clockwise to decrease pilot gas flow. Turn screw counterclockwise to increase pilot gas flow. c. When proper adjustment is obtained, replace screw cap. Gas Input NOTE: Be sure reference pressure tube, combustion-air and vent pipes, and burner enclosure front are in place when clocking the gas meter. 1. Determine gas input. a. Turn off all other gas appliances and pilots. b. Measure time (in seconds) for gas meter test dial to complete one revolution. c. Refer to Table 4 for cu ft of gas per hour. d. Multiply cu ft/hr by heating value of gas (Btu/cu ft) obtained from local gas utility. EXAMPLE: Btu heating input = Btu/cu ft times cu ft/hr Heating value of gas = 1070 Btu/cu ft Time for one revolution of 2-cu-ft dial = 72 sec Gas rate = 100 cu ft/hr (from Table 4) Btu heating input = 1070x100 = 107,000 Btuh e. Measured gas input must not exceed gas input on unit rating plate. 2. To adjust input rate: a. Remove burner enclosure front and cap that conceals adjustment screw for gas valve regulator. b. Turn adjusting screw either counterclockwise (out) to decrease input rate or clockwise to increase rate. When adjusting input rate, do NOT change manifold pressure more than 3.2 minimum to 3.8 maximum in. wc. Make any major adjustments by changing main burner orifices. NOTE: Manifold pressure must always be measured with burner enclosure front removed. The gas meter must always be clocked with burner enclosure front installed. Fig. 6—Tuning Valve Adjustment c. Replace burner enclosure front and measure adjusted gas input rate using method outlines in step 1. d. Replace cap that conceals gas valve regulator adjustment screw. A CAUTION Be sure burner enclosure front is in place after adjustments have been made. 3. Look through sight glass in burner enclosure and check burner and pilot flame. The main burner flame should be clear blue, almost transparent. The pilot flame should be well defined. See Fig. 7. Table 4—Gas Rate in Cu Ft/Hr SECONDS SIZE OF SECONDS SIZE OF FOR ONE TEST DIAL FOR ONE TEST DIAL REVOLU- 1 2 5 REVOLU- 1 2 5 TION cu ft cu ft cu ft TION cu ft cu ft cu ft 10 360 720 1800 50 72 144 360 11 327 655 1636 51 71 141 355 12 300 600 1500 52 69 138 346 13 277 555 1385 53 68 136 340 14 257 514 1286 54 67 133 333 15 240 480 1200 55 65 131 327 16 225 450 1125 56 64 129 321 17 212 424 1059 57 63 126 316 18 200 400 1000 58 62 124 310 19 189 379 947 59 61 122 305 20 180 360 900 60 60 120 300 21 171 343 857 62 58 116 290 22 164 327 818 64 56 112 281 23 157 313 783 66 54 109 273 24 150 300 750 68 53 106 265 25 144 288 720 70 51 103 257 26 138 277 692 72 50 100 250 27 133 267 667 74 48 97 243 28 129 257 643 76 47 95 237 29 124 248 621 78 46 92 231 30 120 240 600 80 45 90 225 31 116 232 581 82 44 88 220 32 113 225 563 84 43 86 214 33 109 218 545 86 42 84 209 34 106 212 529 88 41 82 205 35 103 206 514 90 40 80 200 36 100 200 500 92 39 78 196 37 97 195 486 94 38 76 192 38 95 189 474 96 38 75 188 39 92 185 462 98 37 74 184 40 90 180 450 100 36 72 180 41 88 176 439 102 35 71 178 42 86 172 429 104 35 69 173 43 84 167 419 106 34 68 170 44 82 164 409 108 33 67 167 45 80 160 400 110 33 65 164 46 78 157 391 112 32 64 161 47 76 153 383 116 31 62 155 48 75 150 375 120 30 60 150 49 73 147 367 —6 PILOT FLAME BURNER FLAME 4. High Altitude—Input ratings apply for altitudes up to 2000 feet. Ratings for altitudes above 2000 ft must be 4% less for each 1000 ft above sea level. Temperature Rise—Do NOT operate furnace outside range of temperature rise specified on unit rating plate. Determine air temperature rise as follows: 1. Place thermometers in return and supply ducts as near furnace as possible. Thermometers must not “see” heating element or radiant heat may affect readings. This practice is particularly important with straight-run ducts. 2. When thermometer readings stabilize, subtract return-air temperature from supply-air temperature to determine air temperature rise. 3. Adjust temperature rise by adjus...