Carrier Performance 48VL-A Installation Instructions Manual

Also see for 48VL-A: Owner's information manual

Contents

15Adjust Gas InputThe gas input to the unit is determined by measuring the gas flowat the meter or by measuring the manifold pressure. Measuring thegas flow at the meter is recommended for natural gas units. Themanifold pressure must be measured to determine the input ofpropane gas units.Measure Gas Flow (Natural Gas Units)Minor adjustment to the gas flow can be made by changing themanifold pressure. The manifold pressure must be maintainedbetween 3.2 and 3.8 IN. W.C.REGULATORCOVER SCREWADJUSTMENTSCREWREGULATOR SPRING(PROPANE - WHITE)NATURAL - SILVER)GAS PRESSUREREGULATORADJUSTMENTMANIFOLDPRESSURE TAPINLETPRESSURE TAPON/OFF SWITCHPLASTIC(A07751Fig. 13 -- Single--Stage Gas ValveIf larger adjustments are required, change main burner orificesfollowing the recommendations of national and local codes.NOTE: All other appliances that use the same meter must beturned off when gas flow is measured at the meter.Proceed as follows:1. Turn off gas supply to unit.2. Remove pipe plug on manifold (See Fig. 11) and connectmanometer. Turn on gas supply to unit.3. Record number of seconds for gas meter test dial to makeone revolution.4. Divide number of seconds in Step 3 into 3600 (number ofseconds in one hr).5. Multiply result of Step 4 by the number of cubic feet (cu ft)shown for one revolution of test dial to obtain cubic feet (cuft) of gas flow per hour.6. Multiply result of Step 5 by Btu heating value of gas toobtain total measured input in Btuh. Compare this valuewith heating input shown in Table 4 (Consult the local gassupplier if the heating value of gas is not known).EXAMPLE: Assume that the size of test dial is 1 cu ft, onerevolution takes 32 sec, and the heating value of the gas is 1050Btu/ft3. Proceed as follows:1. 32 sec. to complete one revolution.2. 3600 ÷ 32 = 112.5.3. 112.5 x 1 =112.5 ft3 of gas flow/hr.4. 112.5 x 1050 = 118,125 Btuh input.If the desired gas input is 115,000 Btuh, only a minor change in themanifold pressure is required.Observe manifold pressure and proceed as follows to adjust gasinput:1. Remove regulator cover screw over plastic adjustmentscrew on gas valve (See Fig. 13).2. Turn plastic adjustment screw clockwise to increase gasinput, or turn plastic adjustment screw counterclockwise todecrease input (See Fig. 13). Manifold pressure must bebetween 3.2 and 3.8 IN. WC.FIRE AND UNIT DAMAGE HAZARDFailure to follow this warning could result in personalinjury or death and/or property damage.Unsafe operation of the unit may result if manifold pressureis outside this range.! WARNING3. Replace regulator cover screw on gas valve (See Fig. 13).4. Turn off gas supply to unit. Remove manometer frompressure tap and replace pipe plug on gas valve. (See Fig.11.) Turn on gas to unit and check for leaks.Measure Manifold Pressure (Propane Units)Refer to propane kit installation instructions for properly checkinggas input.NOTE: For installations below 2,000 ft (610 m), refer to the unitrating plate for proper propane conversion kit. For installationsabove 2,000 ft (610 m), contact your distributor for proper propaneconversion kit.Check Burner FlameWith control access panel (see Fig. 19) removed, observe the unitheating operation. Watch the burner flames to see if they are lightblue and soft in appearance, and that the flames are approximatelythe same for each burner. Propane will have blue flame (See Fig.12). Refer to the Maintenance section for information on burnerremoval.Table 4 – Heating InputsHEATING INPUT(BTUH)NUMBER OF GAS SUPPLY PRESSURE (IN. W.C.) MANIFOLD PRESSURENUMBER OFORIFICES Natural{ Propane*{MANIFOLD PRESSURE(IN. W.C.)ORIFICES Min Max Min Max Natural{ Propane*†40,000 2 4.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.060,000 2 4.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.090,000 3 4.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0115,000 3 4.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0130,000 3 4.0 13.0 11.0 13.0 3.2∼3.8 10.0∼11.0*When a unit is converted to propane, different size orifices must be used. See separate, natural ---to ---propane conversion kit instructions.{Based on altitudes from sea level to 2000 ft (610 m) above sea level. In U.S.A. for altitudes above 2000 ft (610 m), reduce input rating 4 percent for each addi-tional 1000 ft (305 m) above sea level. In Canada, from 2000 ft (610 m) above sea level to 4500 ft (1372 m) above sea level, derate the unit 10 percent.48VL-- A