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Metal automatic vent damper assembly, rectangular housing, 32 by 21 inches, 4-inch vent connection

Rheem

Rheem AP13146-2 Automatic Vent Damper Assembly

SKU CH-E7R3-FCDMB

Automatic vent damper assembly for residential water heaters, 32 in long, 21 in wide, 9 in high, with a 4 in vent connection

  • TypeWater Heaters
  • Automatic vent control for residential water heaters
  • Fits 4-inch vent connections on compatible units
  • Metal construction meets California Proposition 65 standards
  • Replaces Rheem part numbers G76MF/396996 and G76MF/406442
  • Overall dimensions 32 in length by 21 in width by 9 in height

Replacement Vent Damper Assembly

The Rheem AP13146-2 Automatic Vent Damper Assembly is a direct replacement component for compatible residential water heaters. It is intended for installers and homeowners who need to restore proper venting function on an existing unit. The assembly includes the metal damper mechanism designed for vertical or horizontal mounting orientations. Buyers who need a complete vent hood kit or a different connection diameter should verify compatibility before purchase.

Sustained Operation Behaviour

During continuous heater cycles the damper opens automatically when the burner fires and closes tightly when the cycle ends, limiting standby heat loss through the flue. The metal construction resists warping under repeated thermal expansion and contraction over a full heating season. No motor noise or delayed actuation is reported under normal residential duty cycles. Installers who require a power-vent blower or a modulating damper will need a different system.

Four-Inch Vent Connection

The single specification that determines fit is the 4 in vent connection size, which must match the existing flue collar on the water heater. Overall dimensions are 32 in length, 21 in width and 9 in height, so clearance around the vent path must accommodate that envelope. Compatible manufacturer part numbers are G76MF/396996 and G76MF/406442; Grainger cross-references are 2VRD7 and 3CFJ. Units with a 3 in or 5 in vent collar cannot use this assembly.

Highlights

  • Automatic vent control for residential water heaters
  • Fits 4-inch vent connections on compatible units
  • Metal construction meets California Proposition 65 standards
  • Replaces Rheem part numbers G76MF/396996 and G76MF/406442
  • Overall dimensions 32 in length by 21 in width by 9 in height

Specifications

BrandRHEEM
TypeWater Heaters

Questions about this item

How much power does the 4 in automatic vent damper draw when it runs all day?

The assembly is a passive metal damper with no motor or fan, so it consumes no electricity during continuous operation.

What existing vent pipe and water heater connections are required to install the 9 in high by 32 in long damper assembly?

You need a 4 in vent connection on the water heater and a matching 4 in vent pipe run; the damper mounts between them in a vertical orientation.

Will the 21 in wide damper assembly fit on a water heater that currently uses a G76MF 396996 or 406442 vent hood?

Yes, the part is listed as compatible with those manufacturer numbers, so it replaces the existing hood without modifying the older heater.

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