Condensate trap and neutralizer

Condensing equipment recovers latent heat from the flue gas, and that recovery produces water: gallons per day in winter on a hard-working tankless unit. The condensate is mildly acidic, which is why some installations run it through a neutralizer before it enters a drain, and why the drain path must be approved material.

The condensate trap holds a water seal that stops flue gas escaping through the drain. If the trap dries out, is blocked, or fills because the drain is clogged, the unit loses its sealed path and reports blockage codes: Rinnai documents a full condensate trap as one of the two named causes of code 10.

The service visit empties and checks the trap, confirms the drain flows, and tops up the seal where the manual requires it. Heat-pump units produce their own condensate from the air they dehumidify, with the same drain and flow checks applying.