Carrier Performance 48VR-A Installation Instructions Manual

Also see for Performance 15 48VR-A: Owner's information manual Owner's information manual

Contents

16MANIFOLDBURNERBURNER FLAMEC99021Fig. 12 -- Monoport BurnerCheck Gas Heating ControlStart and check the unit for proper heating control operation asfollows (see furnace lighting instructions located on the inside ofthe control access panel):1. Place room thermostat SYSTEM switch in the GAS HEATposition and the fan switch in AUTO position.2. Set the heating temperature control setting several degreeshigher than the room temperature reading.3. The induced--draft motor will always start on high speed forthe ignition sequence, regardless of the heating stage called.4. After a pre--purge time of 15 sec with the induced--draft mo-tor on high speed, the sparker will be energized for 3--to--8sec, and the gas valve will be energized on low stage. If theburners do not light, there is a 20--sec delay before anotherignition attempt. If the burners still do not light by the 4 thconsecutive ignition attempt, there is a lockout. To reset thelockout, break the 24--v power to W1 and W2.5. Once flame is established the integrated gas unit controller(IGC) will look for 24--v power to W1 and W2. If there is24--v power to W1 only, the IGC will switch the induced--draft motor down to low speed and maintain low stage onthe gas valve. If there is 24--v power to both W1 and W2,the IGC will maintain the induced--draft motor on highspeed and switch the gas valve to high stage.6. With the desired temperature set several degrees higher thanthe room temperature, most thermostats will energize lowand high stage. Verify that the gas valve is energized onhigh stage and the induced--draft motor is on high speed.7. Verify proper operation of low stage (induced--draft motoron low speed and gas valve on high stage) by turning theheating temperature control setting down until the desiredtemperature is 1 degree above room temperature. Most ther-mostats will energize low stage only with a 1 degree differ-ential.8. The evaporator fan will turn on 30 sec after the flame hasbeen established. If there is 24--v power to W1 only, the fanwill run on low heat speed. If there is 24--v power to W1and W2, the fan will run on high heat speed. Once the heat-ing coll is satisfied, the IGC will turn the fan off after afield--selectable fan delay of 90, 120, 150, or 180 sec iscompleted.Check Gas InputCheck gas input and manifold pressure after unit start--up (SeeTable 5). If adjustment is required proceed as follows:S The rated gas inputs shown in Table 5 is for altitudes from sealevel to 2000 ft (610 m) above sea level. These inputs are basedon natural gas with a heating value of 1025 Btu/ft3 at 0.60specific gravity, or propane gas with a heating value of 2500Btu/ft3 at 1.5 specific gravity.IN THE U.S.A.:The input rating for altitudes above 2,000 ft (610 m) must bereduced by 4% for each 1,000 ft (305 m) above see level.For installations below 2,000 ft (610 m), refer to the unit ratingplate.For installations above 2,000 ft (610 m). multiply the input on therating plate by the derate multiplier in Table 3 for correct input rate.If the natural gs is not de--rated by the utility company refer toTable 4 for correct orifice sizes and manifold pressures.Table 3 – Altitude Derate Multiplier for U.S.A.*ALTITUDE FT (M) PERCENT OF DERATE DERATE MULTIPLIERFACTOR{0--- 2000(0--- 610) 0 1.002001--- 3000*(610--- 914) 8--- 12 0.903001--- 4000(915--- 1219) 12--- 16 0.864001--- 5000(1220--- 1524) 16--- 20 0.825001--- 6000(1524 --- 1829) 20--- 24 0.786001--- 7000(1829--- 2134) 24--- 28 0.747001--- 8000(2134--- 2438) 28--- 32 0.708001--- 9000(2439--- 2743) 32--- 36 0.669001--- 10,000(2744--- 3048) 36--- 40 0.62*In Canada see Canadian Altitude Adjustment.{Derate multiplier factors are based on midpoint altitude for altitude range.IN CANADA:The input rating for altitudes from 2,000 (610 m) to 4,500 ft (1372m) above sea level must be derated 10% by an authorized GasConversion Station or Dealer.EXAMPLE:90,000 Btu/hr Input Furnace Installed at 4300 ft.Furnace Input Rate atSea LevelX Derate MultiplierFactor= Furnace Input Rate atInstallation Altitude90,000 X 0.90 = 81,000When the gas supply being used has a different heating value orspecific gravity, refer to national and local codes, or contact yourdistributor to determine the required orifice size.UNIT DAMAGE HAZARDFailure to follow this caution may result in reduced unitand/or component life.Do Not redrill an orifice. Improper drilling (burrs,out--of--round holes, etc.) can cause excessive burner noiseand misdirection of burner flame. If orifice hole appearsdamaged or it is suspected to have been redrilled, checkorifice hole with a numbered drill bit of correct size.! CAUTIONAdjust 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(s). The manifold pressure(s) must be maintainedbetween 3.2 and 3.8 IN. W.C. for high stage and between 1.4 and2.0 IN. W.C. for low stage (208/230 VAC models). For 460 VACmodels, manifold pressure must be maintained between 3.2 and 3.8IN. W.C.48VR-- A