NOTE − The exhaust collar on all models is sized to ac- commodate 2" Schedule 40 vent pipe. Contact the Ap- plication Department for more information concerning sizing of vent systems which include multiple pipe sizes.
NOTE − All horizontal runs of exhaust pipe must slope back toward unit. A minimum of 1/4" (6mm) drop for each 12" (305mm) of horizontal run is mandatory for drainage.
NOTE − Exhaust pipe MUST be glued to furnace exhaust fittings.
NOTE − Exhaust piping should be checked carefully to make sure there are no sags or low spots.
Use the following steps to correctly size vent pipe diameter.
IMPORTANT
Do not use screens or perforated metal in exhaust or intake terminations. Doing so will cause freeze−ups and may block the terminations.
| Furnace | 070, 090, 110 | |
1 | Capacity? | ||
btuh | |||
|
| ||
|
| Standard or | |
2 | Which termination? | Concentric? | |
|
| See table 5 | |
3 | Which needs | Intake or | |
most elbows? | |||
exhaust? | |||
| |||
|
| ||
4 | How many? |
| |
5 | Desired pipe size? | 2", 2−1/2", 3" | |
6 | What is the altitude? |
| |
7 | Use table 7 to find |
| |
max intake or |
| ||
| exhaust pipe length. |
|
FIGURE 15
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