High-efficiency condensing furnaces produce acidic condensate during regular operation. This condensate must be removed from the furnace and delivered to the building sanitary system effectively in order to avoid furnace corrosion and reduced equipment service life (Figure 10).

The following practices are not consistent with quality furnace installations and are not compliant with the BC Plumbing Code or the FortisBC Furnace and Boiler Replacement Program requirements:

Draining Condensate to the Exterior

The BC Plumbing Code requires that all new condensate plumbing be connected to the building sanitary drainage system either through a plumbed connection or indirectly through a floor drain (or similar). Condensate expelled directly to the exterior is not Code-compliant and may freeze during cold weather, tripping the float switch and prematurely shutting down the furnace unit (Figure 11).

Trap Between Condensate Line and Sanitary System

Plumbed connections to the building sanitary system must include a trap between the condensate line and the sewage pipe as required by BC Plumbing Code (Figure 12). As the condensate is typically acidic, in many jurisdictions it must also be neutralized prior to being discharged into the sanitary system (Figure 13).

Crimped Condensate Line

Condensate lines that have bends along their routing may become crimped (Figure 14). Crimped condensate lines can obstruct the flow of acidic condensate causing build-up and early failure of the new furnace unit.

Proper Furnace Placement and Leveling

Most manufacturers recommend leveling or tipping the furnace to promote condensate drainage out of the system. If the acidic condensate is not effectively removed, it can corrode furnace components and reduce the service life of the equipment.

Solutions

• A floor drain or other sanitary system connection may not always be available in the mechanical room. Where this is the case, a pump can be utilized to move condensate to a higher elevation sanitary connection for disposal (Figure 15).

• Where the condensate routing requires turns and bends, braided tubing or rigid PVC tubing is a practical solution to reduce the risk of crimping.
• Always confirm with the Authority Having Jurisdiction (AHJ), whether a condensate neutralizer (e.g. limestone chips) is required.