HVACopediaAllied · Furnace troubleshooting
Platform installation of a horizontal unit
What is going on
Used for horizontal units set on a raised platform or suspended in an attic or crawl space.
Check in this order
- Select a location that keeps service and required clearances.
- Build a raised wooden frame and cover it with plywood. Use an auxiliary drain pan under the unit if installed over finished space.
- Leave 8 in of service clearance below the unit for the condensate trap.
- Provide a service platform in front of the unit. In a crawl space, cement blocks can serve as support.
- Route the auxiliary drain so water is easy to notice.
- If needed, use a condensate pump rated for condensing furnaces. Protect the discharge line to the outside from freezing.
- Install exhaust, condensate and intake piping per the instructions.
Applies to: Horizontal installs in attic or crawl space
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Source: Allied 92G1UH installation instructions manual, p. 16. 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.