US Patent 8931438 Condensing gas appliance and condensate trap therefor

A condensing fuel-fired appliance has a condensate trap that includes a trap body; a float; a flue gas inlet port for the introduction of flue gas into the interior region of the trap body; a condensate outlet port for the discharge of condensate from the interior region; and a flue gas outlet port for the discharge of flue gas from the interior region of the trap body. The float is configured to move in response to condensate collected in the interior region of the trap body to a position to substantially block the discharge of flue gas from the interior region through the flue gas outlet port. The float is also configured to move to a position to substantially block the discharge of flue gas from the interior region through the condensate outlet port when there is little or no condensate in the interior region of the trap body.