The ornamental design for a waterheaterairductadapter, as shown and described.
FIG. 1 is a front perspective view of a water heater air duct adapter showing our new design.
FIG. 2 is a front view thereof.
FIG. 3 is a rear view thereof.
FIG. 4 is a left view thereof.
FIG. 5 is a right view thereof.
FIG. 6 is a top view thereof.
FIG. 7 is a bottom view thereof.
FIG. 8 is a front perspective view thereof, showing the water heater air duct adapter in an open configuration, for clarity of illustration; and,
FIG. 9 is a front view thereof, showing the water heater air duct adapter in an open configuration, for clarity of illustration.
The broken line showing of a water heater air duct adapter is included for the purposes of illustrating portions of the article and forms no part of the claimed design. The dot-clash broken lines define the bounds of the claimed design and form no part thereof.