Allied Furnace: Exhaust transitions in upflow and horizontal runs
Exhaust transitions in upflow and horizontal runs on a Allied furnace: Figures 22 and 23 in the Allied manual show typical exhaust connections for upflow and horizontal runs. The short version: you can go up in pipe size, but only where the manual allows it, and the exhaust and intake pipe stay the same diameter. Take a look at the figures before cutting any pipe.
Applies to: Upflow and horizontal direct or non-direct vent
Common causes of exhaust transitions in upflow and horizontal runs
- Pipe size transition made in the wrong place or run direction
- Long 2 in. section or step-up that traps condensate
- Exhaust and intake pipe of different diameters
How to fix exhaust transitions in upflow and horizontal runs: step by step
- In upflow direct or non-direct vent, make the transition in vertical runs only.
- In horizontal runs, keep any 2 in. step-up as short as possible and keep the bend within 45 degrees.
- Keep the maximum straight 2 in. section at the exhaust connection at 12 in.
- Use the same diameter for the exhaust pipe and the intake pipe.
- Compare your layout to figures 22 and 23 before gluing.
If the unit shows an error code, look it up: Allied Furnace codes
Models
92G1UH92G1UH0450892G1UH0451292G1UH0700892G1UH0701292G1UH0901292G1UH0901692G1UH1101692G1UH1102092G1UH1352095G1UHA93UHA95UH
Source: Allied 92G1UH installation manual, p. 20 (PDF p. 20). Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.