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Filter placement for upflow furnace in horizontal configuration
What is going on
Before you lay an upflow Trane furnace on its side, think about the filter first. The manual says a filter must never sit inside or outside the cabinet directly above the blower assembly in a horizontal setup. Confirm where the return and filter will end up before the unit is set.
Likely causes
- Filter placed directly above the blower in a horizontal install
- No remote filter or upstream filter provision in the ductwork
- Wrong conversion kit for the cabinet width
Check in this order
- Do not place the filter directly above the blower, inside or outside the cabinet.
- Use a remote filter grille, or install the filter in the ductwork upstream of the furnace.
- For conversion, use filter kit BAYFLTR203 (17.5 in cabinet), BAYFLTR204 (21 in) or BAYFLTR205 (24.5 in). These include the filters and brackets needed for horizontal filters.
- Match the kit to your cabinet width before ordering.
- After installation, confirm the filter is seated and no air bypasses it.
Applies to: Upflow furnace in horizontal configuration
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Source: Trane AUH1B080A9421B installer's manual, p. 17. Written in our own words; check the manual for your exact model.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.