Vent slope, support and roof termination

What is going on

Install exhaust and intake piping so condensate drains back toward the boiler and the piping is secured.

Check in this order

1. Slope the exhaust piping upward toward the terminal at a minimum of 1/4 in per foot so condensate drains back to the boiler. Use 1/2 in per foot where condensation is heavy.
2. Slope the intake piping downward toward the boiler to prevent water collecting in it.
3. Secure all exhaust and intake piping to the wall or structure for rigidity.
4. Support the pipe horizontally and vertically at the maximum spacing given in the manual (see notes for conflicting values).
5. Install a roof flashing where the pipe passes through the roof to prevent leaks.
6. On roofs, point the discharge away from the roof pitch and keep the intake and exhaust at least 24 in apart.
7. Install a 1/2 in x 1/2 in galvanized screen in the vent end if desired (optional).
8. Insulate exhaust piping that runs through unconditioned space to limit condensate.
9. For vertical exhaust, fit an additional condensate drain. All fittings must be ULC S636 approved.
10. Keep the terminal at least 12 in above grade or expected snow level, and at least 12 in above highest expected snow level for roof terminations (18 in in Canada).

More boiler guides

• 0-10 VDC input to modulate firing rate (Mode 5)
• Annual maintenance and inspection
• Blank display
• Boiler pressure keeps dropping / FILL shows
• Boiler shows FILL and will not fire
• Cleaning the combustion side of the heat exchanger