The right water heater door gasket depends on where the seal sits and which heater model you have. The A. O. Smith manifold door gasket is the most directly relevant option for a manifold-door repair, while the Z kit combines a burner-door gasket with thermocouple parts for certain Rheem and Richmond heaters. The other products listed are element or supply-line seals, not burner-door gaskets, so consider them only for those specific leak locations.
| Product | Best suited for | Seal location |
|---|---|---|
| A. O. Smith 100112699 | Matching A. O. Smith manifold-door replacement | Manifold door |
| Z TC-KIT | Specified Rheem and Richmond repairs | Burner door and thermocouple assembly |
| Supplying Demand SP6708 | Electric element replacement | Heating element |
| LASCO 10-1403 | Copper flex-connector gasket replacement | Water connection |
| Danco 65884B | Flexible supply-line leak repair | Supply connection |
A. O. Smith 100112699 Manifold Door Gasket
Best for: A buyer replacing a manifold door gasket and confirming that this specific part matches the water heater. This is the most directly relevant product in the list for a water heater door gasket because its supplied description identifies it as a manifold door gasket.
The listed feature is “gasket, manifold door.” That identifies the intended sealing location, but the product details provided do not specify dimensions, compatible model numbers, material, or installation instructions. Check the heater’s model and parts documentation before ordering rather than relying only on the brand name.
- Why it was selected: It is explicitly identified as a manifold door gasket, rather than as a plumbing washer or an electric-element seal.
- Limitation: The supplied product information gives no model-fit list. Do not assume it fits every A. O. Smith heater or every burner-door assembly.
Choose this if your repair calls for the identified A. O. Smith manifold door gasket. Avoid using it as a substitute for a water-line washer or an electric heating-element gasket; those seals serve different connections.
Z TC-KIT Thermocouple Gasket Kit
Best for: Owners repairing a compatible Rheem or Richmond gas water heater who need a burner-door gasket along with thermocouple-related parts. The kit includes a high-temperature silicone burner-door gasket, a universal 24-inch thermocouple, four speed clips, four T20 Torx screws, and a T20 Torx driver.
The listing describes the kit as a replacement for OEM parts RP20064 and SP20064 and says it is intended for a range of Rheem and Richmond models, including many FVIR models made after July 2003. It is also presented as a repair option for a pilot that will not stay lit, a faulty thermocouple, or a cracked or leaking burner-door gasket.
- Why it was selected: It combines a burner-door gasket with related repair components and a driver, making it more complete than a gasket-only replacement.
- Limitation: Its stated fit is not universal. Confirm the heater model and the replacement-part reference before installation.
Choose this if the heater is within the stated Rheem or Richmond application and the repair requires the included components. Avoid it if you need only a different brand’s manifold gasket or a seal for a water-line connection.
Supplying Demand SP6708 Element Gasket
Best for: A buyer replacing a seal at an electric water-heater element, not a burner or manifold door. The product is described as an element gasket made from synthetic rubber, with EPDM listed as the material.
The stated dimensions are a 1.23-inch inner diameter, 1.46-inch outer diameter, and 0.15-inch thickness. The listing also gives a durometer value of 70 on the 00 scale. These measurements can help with comparison, but they do not by themselves prove compatibility with a particular heater or element.
- Why it was selected: It is a water-heater replacement gasket and helps distinguish an element seal from a door gasket when diagnosing a leak.
- Limitation: It is not identified as a burner-door or manifold-door gasket. The listing recommends installation by a qualified technician and says to turn off power before working on the heater.
Choose this only when the leaking or replaced component is the electric heating element and the part specifications match. Avoid it for gas-burner door repairs.
LASCO 10-1403 Flex Connector Gaskets
Best for: Replacing a rubber gasket inside a compatible copper water flex connector. The product information says the gaskets fit inside a 3/4-inch nut and are intended as replacements for copper water flex.
This is a plumbing-connection seal, not a seal for the heater’s burner compartment or manifold door. The fitting location matters: a gasket that fits a connector nut cannot be assumed to fit a combustion-chamber door or an electric element.
- Why it was selected: It is a water-heater-related replacement gasket for a clearly described connection point, helping buyers avoid confusing plumbing leaks with door-seal problems.
- Limitation: The provided details do not give additional dimensions or compatibility information for specific connector brands. Confirm the connector type and gasket fit.
Choose this if the leak is at the appropriate copper flex-connector nut. Avoid it if the water is escaping around a burner door, manifold, or heating element.
Danco 65884B Supply Line Washer
Best for: Repairing a leak at a compatible flexible water-heater supply-line connection. This one-pack washer is made of black rubber and is designed for use with a 3/4-inch flexible supply line. The listed purpose is to provide a positive seal at the supply connection.
Although the product description calls it a water-heater part, it is not a burner-door gasket. A leak at a supply connection and a leak at a combustion door require different parts and repair procedures.
- Why it was selected: Its stated 3/4-inch flexible supply-line application makes it relevant to water-heater seal repairs at the plumbing connection.
- Limitation: It is a single rubber washer for a supply-line connection. The supplied details do not establish that it fits every flexible line or any door assembly.
Choose this if the problem is a leaking flexible supply-line connection and the washer matches the fitting. Avoid using it in place of a specified manifold or burner-door gasket.
Buying Guide: How to Choose a Water Heater Door Gasket
Where is the leak or damaged seal?
Identify the exact sealing location before buying a part. A manifold or burner-door gasket seals a door or access assembly. An element gasket seals around an electric heating element. A supply-line washer or flex-connector gasket seals a plumbing connection. These parts have different shapes, materials, dimensions, and jobs; they are not interchangeable simply because each is called a gasket or washer.
If you cannot tell where the leak originates, avoid ordering based only on the word “water heater.” Look for visible water at a plumbing fitting or consult the heater’s parts diagram and service documentation. A gas-burner door repair is different from a water-line leak and should be handled with the appropriate safety procedures.
How do you confirm that a door gasket fits?
Use the heater’s complete model number and, when available, the original part number. Compare the replacement description with the parts list for the exact heater. The A. O. Smith item is identified as a manifold door gasket, while the Z kit names RP20064 and SP20064 and describes applications for certain Rheem and Richmond heaters. Those descriptions are useful starting points, not proof that either part fits every model from those brands.
Do not choose a gasket solely by appearance in a product image. Check the shape, mounting arrangement, material requirements, and part reference in the heater documentation. If the replacement part’s application is unclear, ask a qualified technician or the manufacturer for confirmation.
Do you need a gasket alone or a repair kit?
A gasket-only part may suit a straightforward replacement when the original seal is the only required component and the part match is confirmed. A kit such as the Z TC-KIT includes a burner-door gasket, thermocouple, clips, Torx screws, and a driver. That combination may be useful when the repair calls for those listed pieces, but extra components do not make a kit suitable for a different heater.
Before selecting a kit, compare its contents and stated replacement references with the repair instructions. If the repair does not require the additional parts, a kit may not be the right choice. Do not replace unrelated components without confirming that they are needed.
What do dimensions and materials tell you?
Dimensions matter most when they are specified for the exact sealing application. The Supplying Demand product lists inner diameter, outer diameter, and thickness for an electric-element gasket. The LASCO product is described as fitting inside a 3/4-inch nut, and the Danco washer is specified for a 3/4-inch flexible supply line. Those details apply to the stated connection types; they do not establish suitability for a burner door.
Material also matters because seals are designed for their specific operating location. For example, the Z kit identifies its burner-door gasket as high-temperature silicone, while the element gasket lists EPDM. Do not substitute a generic rubber washer for a combustion-area seal unless the heater’s parts documentation specifically allows it.
When should a qualified technician handle the repair?
Use a qualified technician when the work involves gas-burner components, a thermocouple, a burner door, or any repair you cannot confidently identify. The Supplying Demand listing specifically recommends professional installation and directs users to turn off power before work on an electric water heater. Follow the heater manufacturer’s safety and service instructions for the specific repair, and do not operate the heater with a damaged or incorrectly installed seal.
Frequently Asked Questions
Are water heater door gaskets interchangeable?
No. Door gaskets vary by heater model and assembly. A manifold or burner-door gasket is also different from an electric-element gasket or a supply-line washer.
Which listed product is most directly a water heater door gasket?
The A. O. Smith 100112699 is explicitly described as a manifold door gasket. The Z TC-KIT includes a high-temperature burner-door gasket for the stated Rheem and Richmond applications.
Can a supply-line washer fix a leaking burner door?
No. The Danco and LASCO products are described for water connections, not burner doors. Use a door gasket specified for the heater’s model and assembly.
How can I check whether a gasket fits my water heater?
Check the heater’s model number, parts diagram, and original gasket or replacement-part number. Confirm the intended location and fit before ordering; brand name alone is not enough.
Does a pilot that will not stay lit always mean the gasket is bad?
No. The Z kit listing names a faulty thermocouple and a cracked or leaking burner-door gasket as possible issues, but a pilot problem can require diagnosis. Identify the cause before replacing parts.
Can I install a water heater gasket myself?
That depends on the gasket location, heater type, and your experience. The listed element gasket calls for qualified professional installation, and gas-burner or thermocouple repairs should follow the manufacturer’s service instructions and appropriate safety procedures.