Bosch BGH96M060B3A Installation, Operation And Maintenance Manual

Also see for BGH96 Series: Troubleshooting guide Installation instructions User's information manual

Contents

2 2 | Bosch 96% AFUE Gas Furnace Installation, Operation & Maintenance04.2019 | Bosch Thermotechnology Corp.Data subject to change7.4 Filter ArrangementCAUTION: FIRE HAZARD Never install a filter on the supply air side. Filters shouldalways be installed on return air side of system.WARNING: CARBON MONOXIDE AND POISONING HAZARD Never operate a furnace without a filter or with filteraccess door removed.Filter sizeThe Bosch 96% AFUE Gas Furnace BGH96 series does not include a fi lter from themanufacturer. The fi lter and fi lter rack must be fi eld supplied and fi eld installed. Ahigh velocity fi lter is recommended, see recommended fi lter size and type in Table2. One of the most common causes of furnace malfunctions is a blocked or dirtyfi lter. The fi lter must be inspected monthly for dirt accumulation and replaced ifnecessary.Filter typeAir velocity through disposable fi lters may not exceed 300 feet per minute (FPM).All velocities over this require the use of high velocity fi lters. If a normal speeddisposable fi lter is used and air speed exceeds 300 feet per minute (FPM), two sidereturns or one side return and the bottom return may be needed. For airfl ow, referto Tables 3 & 4.NOTICE: If disposable fi lters are used, air passage through fi ltersshould be increased to twice the size of original airopening by using a transition duct or using two filters in Vshape (see Fig. 19) in normal duct size.Figure 19Furnace cabinet width Filter size Filter typeSide return Bottom return17-1/2 16X25 16X25 High Velocity (600 FPM)21 16X25 20X25 High Velocity (600 FPM)24.5 16X25 24X25 High Velocity (600 FPM)Table 2 Manufacturer recommended high velocity filter sizes - InchSide returnLocate the 4 knockout locations. These indicate the size of the cut-out to be madein the furnace side panel. Refer to Fig 20, "Side Return Knockout Markings".Figure 20Front ofFurnaceCut out forside returnSide return knockout markingsDimensions of return air "cut out" must match those shown in Figure 1.DO NOT cut outside of the "knockout" markings.Install the side fi lter rack (fi eld supplied) following the instructions provided withthat accessory. If a fi lter(s) is provided at another location in the return air system,the duct work may be directly attached to the furnace side panel.Bottom Return filtersFilter(s) may be located in the duct system outside the furnace using an externalduct fi lter box attached to the furnace plenum or at the end of the duct in a returnfi lter grille(s). The use of straps and/or supports is required to support the weightof the external fi lter box.