Carrier 58DXT Operating Instructions Manual

Also see for 58DXT: User's information manual Service and maintenance instructions

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Carrier 58DXT Operating Instructions Manual Manual pdf 20 page image

EXAMPLE: (High-heat operation at 0—2000 ft altitude)Furnace input from rating plate is 80,000 BtuhBtu heating input = Btu/cu ft X cu ft/hrHeating value of gas = 1050 Btu/cu ftTime for 1 revolution of 2-cu ft dial = 92 secGas rate = 80 cu ft/hr (from Table 10)Btu heating input = 78 X 1050 = 81,900 BtuhIn this example, the orifice size and manifold pressureadjustment is within ±2 percent of the furnace input rate.NOTE: Measured gas inputs (high heat and low heat) must bewithin ±2 percent of that stated on furnace rating plate wheninstalled at sea level or derated per that stated above when installedat higher altitudes.m. Remove jumper across R, W/W1, and W2 thermostatconnections to terminate call for heat.5. Set temperature rise.Place SW-2 in ON position. Jumper R to W/W1 and W2 tocheck high-gas-heat temperature rise. To check low-gas-heattemperature rise, remove jumper to W2. Determine air tem-perature rise for both high and low heat using the followingsteps. DO NOT exceed temperature rise ranges specified onunit rating plate for high and low heat.a. Place duct thermometers in return and supply ducts as nearfurnace as possible. Be sure thermometers do not see heatexchangers so that radiant heat will not affect thermometerreadings. This is particularly important with straight-runducts.b. When thermometer readings stabilize, subtract return-airtemperature from supply-air temperature to determine tem-perature rise.NOTE: If temperature rise is outside this range, first check:(1.) Gas input for low- and high-heat operation.(2.) Derate for altitude if applicable.(3.) Return and supply ducts for excessive restrictionscausing static pressures greater than 0.50-in. wc.c. Adjust air temperature rise by adjusting blower speed.Increase blower speed to reduce temperature rise. Decreaseblower speed to increase temperature rise. For high heat,speed selection can be med-high, med (5-speed blowersonly), or med-low (factory setting). For low heat, speed tapselection can be low (factory setting), med-low, or med(5-speed blowers only).Table 10—Gas Rate (Cu Ft/Hr)SECONDSFOR 1REVOLUTIONSIZE OF TEST DIAL SECONDSFOR 1REVOLUTIONSIZE OF TEST DIAL1cu ft2cu ft5cu ft1cu ft2cu ft5cu ft101112131436032730027725772065560055551418001636150013851286505152535472716968671441411381361333603553463403331516171819240225212200189480450424400379120011251059100094755565758596564636261131129126124122327321316310305202122232418017116415715036034332731330090085781878375060626466686058565453120116112109106300290281273265252627282914413813312912428827726725724872069266764362170727476785150484746103100979592257250243237231303132333412011611310910624023222521821260058156354552980828486884544434241908886848222522021420920535363738391031009795922062001951891855145004864744629092949698403938383780787675742001961921881844041424344908886848218017617216716445043942941940910010210410610836353534337271696867180178173170167454647484980787675731601571531501474003913833753671101121161203332313065646260164161155150Fig. 15—Redundant Automatic Gas Control ValveA97358ON/OFFSWITCHINLETPRESSURETAPONOFFMANIFOLDPRESSURETAPLOW-FIREADJUSTMENTALLEN SCREW(UNDER CAP)HIGH-FIREADJUSTMENTALLEN SCREW(UNDER CAP)Fig. 16—Burner Flame A89020BURNER FLAMEBURNERMANIFOLD20