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Manufacturer Resources
Product Specs
- Base Material:
- PVC
- Connection Type:
- PVC
- Volume:
- 1.172
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Drainage Products
- Product Type:
- Drain
- Product Finish:
- Cast Iron Grate
- Product Material:
- PVC
- Product Weight:
- 10.55
OATEY 78042 – Frequently Asked Questions
1) What pipe does the Oatey 78042 roof drain connect to?
The 78042 has a 2 inch PVC outlet, so it solvent welds to 2 inch PVC DWV pipe. The drain body itself is PVC, so it is a straight glue joint, no gaskets or clamps. If your roof leader is cast iron or ABS, you need a transition fitting or a drain built for that material.
2) Does the Oatey 78042 come with the dome strainer, or do I buy that separately?
The cast iron dome and the dam collar both come with the 78042. You are buying a complete drain assembly: PVC body, cast iron dome strainer on top, and the dam collar. Nothing else to source except the PVC pipe and solvent cement.
3) What is the dam collar on a roof drain for?
The dam collar sits around the drain and holds a shallow pool of water on the roof so runoff is metered off slowly rather than dumping all at once. It is what makes a controlled flow or ponding roof design work. If your roof is not engineered for controlled flow, you can leave the collar off and run the 78042 as a standard drain with just the cast iron dome.
4) Why a cast iron dome instead of a plastic one on a PVC roof drain?
Cast iron takes foot traffic and hail without cracking, and it will not go brittle after years of UV on an exposed roof. That is the part of the drain that gets stepped on by roofers and HVAC techs. The 78042 pairs the cast iron dome with a PVC body, so the buried portion is corrosion proof and the exposed portion is the tough one.
5) Is a 2 inch roof drain big enough, or should I step up?
The 78042 is the 2 inch size. On small roofs, balconies, canopies, equipment platforms, and secondary or overflow duty it is usually the right call. On larger main roof areas the drain size is set by roof area and rainfall rate in your local code, so if your calculation calls for 3 or 4 inch, use the larger body rather than doubling up on 2 inch drains.
6) Can I use the Oatey 78042 on a concrete deck or only wood framing?
Either works. The drain is a PVC body with a 2 inch PVC outlet and clamps to the roof membrane at the collar, so the deck material underneath does not drive the drain choice. What matters is that you have clear access below to solvent weld the 2 inch PVC leader.
7) What is the Oatey part number and UPC for the 2 inch PVC roof drain with cast iron dome?
Oatey 78042 is the manufacturer part number, UPC 038753780429. Order by 78042 to get the PVC body with the cast iron dome and dam collar together.
How fast can I get the OATEY 78042 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the
continental
U.S.
Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the OATEY 78042 come with a warranty?
Absolutely. The OATEY 78042 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the OATEY 78042?
You can call, text, or email our expert support team for fast answers. We’re here to help with
product
selection,
installation tips, and troubleshooting. Contact Us
Why buy the OATEY 78042 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support,
and
rewards on
every order.
Our team is always ready to help you choose the right product for your project.