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Z-Flex 3" or 4" Diameter Vent+Backflow Preventer, 6" length

by Z-Flex
Original price $48.95 - Original price $69.95
Original price
$48.95 - $69.95
Current price $48.95


Made in America

Useful in colder climates for preventing freezing air from flowing back into the heat exchanger and freezing it and damaging the heater


• Vent material: AL29-4C stainless steel
• 6" in length
• Single wall
• Certification: Tested to meet or exceed Underwriters Laboratories (UL) spec UL1738 and ULS636
• Approval: Cat II, III, IV venting
• Limited Lifetime Warranty

Compatibility and cross reference:

This item is the same as Takagi, AO Smith, American Heating part number 9007996005. This item is NOT a universal appliance adapter, and cannot be used to connect directly onto the water heater flue opening.

It is compatible with the following tankless water heaters, as shown in their manual:

American Water Heaters GT-510-P/N Indoor Liquid Propane/Natural Gas
American Water Heaters GT-310-P/N Indoor Liquid Propane/Natural Gas
American Water Heaters GT110-P/N Indoor Liquid Propane/Natural Gas
A. O. Smith ATI-510-N/P Indoor Propane/Natural Gas
A. O. Smith ATI-310-N/P Indoor Propane/Natural Gas
A. O. Smith ATI-110-N/P Indoor Propane/Natural Gas
GSW GSWT-110/310
GSW GSWT-520/540
Marey 5L
Marey 10L
Reliance Water Heaters TS-510-GI
Reliance Water Heaters TS-310-GI
Reliance Water Heaters TS-110-GI
State Industries 510 Series
State Industries 310 Series
State Industries 110 Series
Takagi T-T-KJr2 Indoor Propane/NG
Takagi T-K4 Indoor Propane/NG

FAQ (Frequently Asked Question)

Q1: Can this be attached directly onto the tankless water heater?

A1. No. Instead, use the 2ZVB04 for 4" diameter vent pipe or this here for 3" or 5" diameter which also includes a condensation drain.

Installation instructions

Z-Vent SVE Series IV Installation and Maintenance Instructions, 3" to 24",Single & Double Wall

Additional installation notes

• The internal flapper must be 100% closed when the water heater is not running.
• The directional arrow on the label must point in the same direction as the exhaust flow.
• If this part is installed horizontally, it must be perfectly horizontal or slightly angled upwards towards the termination. This will help ensure that the damper closes completely when the water heater
is not running.
• The damper must not be installed in an enclosed section of vent pipe. This allow accessibility to this part.
• Do not install this part in areas with no heating or cooling, such as an attics, because condensation can drain back downwards into the heater and freeze and potentially block the flapper. Alternatively, buy this part here.