Revision B (WB-I&O-Rev B) reflects changes made to the
ratings page.
Revision C (WB-I&O-Rev C) reflects changes made to the
orifice on Models 150 and 210.
Revision D (ECO #C02407) reflects the addition of air inlet
pipe materials, Maintenance Section, high altitude, air
pressure switch, new condensate trap image and the
addition of the new vent termination.
Revision E (ECO #C02545) reflects the addition of
references to the safety shutoff testing and instructions,
sediment trap, periodic cleaning of screens in vent
terminations, wall thickness for direct vent terminations,
removal of B149.2 references, approval of the 2" and 3"
concentric vent kits for ULC-S636 and sidewall vent
termination kit number correction.
WB-I&O Rev E
11/08