A collector assembly is provided for directing products of combustion between segments of a flue of a water heater. The assembly includes an insulator at least partially defining a chamber configured to direct products of combustion between the flue segments. The assembly also includes a cover configured to at least partially surround the insulator. The cover is also configured to be coupled to a water tank of the water heater. The insulator in an uncompressed state is dimensioned to extend outwardly from the cover when the insulator is positioned in the cover. The insulator in a compressed state is dimensioned to permit coupling of the cover to the water tank.