1083292-UIM-A-0114Johnson Controls Unitary Products 9SECTION III: FILTERSFILTER INSTALLATIONAll applications require the use of a field installed filter. All filters andmounting provision must be field supplied.Filters must be installed external to the furnace cabinet. DO NOTattempt to install filters inside the furnace.1.Air velocity through throwaway type filters may not exceed 300 feet per minute(91.4 m/min). All velocities over this require the use of high velocity filters.2.Do not exceed 1800 CFM using a single side return and a 16x25 filter. ForCFM greater than 1800, you may use two side returns or one side and the bot-tom or one side return with a transition to allow use of a 20x25 filter.SIDE RETURNLocate the “L” shaped corner locators. These indicate the size of the cut-out to be made in the furnace side panel. Refer to Figure 14.Install the side filter rack following the instructions provided with thataccessory. If a filter(s) is provided at another location in the return airsystem, the ductwork may be directly attached to the furnace side panel.FIGURE 13: DimensionsFRONT33ALEFT SIDECombustion Air InletCondensate Drain(Downflow)ThermostatWiring28.5”Gas PipeEntryElectricalEntryCondensateDrainThermostatWiringRIGHT SIDECondensate Drain(Downflow)14”1”1.5”23”Combustion Air InletGas PipeEntryElectricalEntryCondensateDrainOptional Return AirCutout (Either side)29.5”(For Cladded door add appoximately an additional .75”)CSUPPLY END.56”.56”20”B3”23.8”.56”CombustionAir InletRETURN ENDB24.25”2” VentConnectionOutlet2” VentConnectionOutlet 2” VentConnectionOutletTable 3: Cabinet and Duct DimensionsBTUH (kW)InputNominalCFM (m3 /min)CabinetSizeCabinet Dimensions (Illustrated in Figure 13)A (in) A (cm) B (in) B (cm) C (in) C (cm)60 (17.6) 1200 (34.0) B 17 1/2 44.4 16 3/8 41.6 13 1/4 33.780 (23.4) 1200 (34.0) B 17 1/2 44.4 16 3/8 41.6 14 3/4 37.580 (23.4) 1600 (45.3) C 21 53.3 19 7/8 50.5 16 1/2 41.9100 (29.3) 1600 (45.3) C 21 53.3 19 7/8 50.5 18 1/4 46.4100 (29.3) 2000 (56.6) C 21 53.3 19 7/8 50.5 18 1/4 46.4120 (35.1) 2000 (56.6) D 24 1/2 62.2 23 3/8 59.4 21 3/4 55.2Single side return above 1800 CFM is approved as long as the filtervelocity does not exceed filter manufacturer’s recommendation anda transition is used to allow use on a 20x25 filter.Table 4: Recommended Filter Sizes (High Velocity 600 FPM)CFM(m³/min)CabinetSizeSide(in)Bottom(in)1200 (34.0) B 16 x 25 16 x 251600 (45.3) C 16 x 25 20 x 252000 (56.6) C (2) 16 x 25 20 x 252000 (56.6) D (2) 16 x 25 22 x 25NOTICEFIGURE 14: Side Return Cutout MarkingsSome accessories such as electronic air cleaners and pleatedmedia may require a larger side opening. Follow the instructionssupplied with that accessory for side opening requirements. Do notcut the opening larger than the dimensions for the “Optional ReturnAir Cutout” shown in Figure 13.Front ofFurnaceCornerMarkingsSide ofFurnace