HVACopediaAllied · Furnace troubleshooting
Horizontal clearance figure (values not readable)
What is going on
This one is about Figure 15, the horizontal clearance drawing for the Allied furnace. It covers top, front, back, ends, vent and floor. Read the numbers straight off the printed figure in your manual for those. What we can say is that front clearance in an alcove is 24 in., and 24 in. is also the minimum for front service access, so you can get the burner and blower out later.
Likely causes
- Clearances guessed instead of read from Figure 15
- Insufficient front space for service access
- Furnace set on carpet, tile or other combustible material
Check in this order
- Check the Figure 15 values in the printed manual before setting the unit.
- Keep 24 in. at the front, both for an alcove and for service access.
- Keep 8 in. below the unit for the condensate trap.
- Do not set the furnace directly on carpet, tile or other combustible material other than wood flooring.
- Recheck the final position against the figure once the unit is in place.
Applies to: Horizontal applications, right or left hand discharge
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Source: Allied 92G1UH installation manual, p. 16 (PDF 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.