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Manufacturer Resources
Product Specs
- Air Gap Diameter:
- 4 3/8 IN
- Air Gap Diameter Metric:
- 110 MM
- Body Material:
- Cast Iron
- Outlet Connection Size:
- 2 IN
- Outlet Connection Size Metric:
- 50 MM
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Series:
- Air Gaps
- Valve Size:
- 1 1/4 to 3 IN
- Valve Size Metric:
- 32 to 76 MM
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Backflow Accessories
- Product Type:
- Air Gap
Watts 881378 – Frequently Asked Questions
1) What size drain line does the Watts 0881378 air gap connect to?
The outlet is a 2 inch female NPT threaded connection (50 mm), so it takes 2 inch NPT male pipe or a 2 inch male adapter into your indirect waste line. No soldering or bonding involved, it threads on.
2) Do I need an air gap fitting on a reduced pressure backflow preventer, or can I pipe the relief valve straight to the drain?
A reduced pressure assembly like the Watts 009 or 909 must discharge through an air gap, never a direct connection to the waste line, so that a plugged drain can never back siphon into the relief valve. The 0881378 is the fitting that does that job: it catches the relief discharge in an open funnel and carries it away through a 2 inch female NPT outlet to an indirect waste receptor.
3) How much clearance do I need under the relief valve for this Watts air gap?
Plan the rough-in around a 4-3/8 inch (110 mm) air gap funnel diameter under the relief port, plus the depth of the 2 inch female NPT outlet and the fitting you thread into it. The funnel must sit below the relief opening with an open gap between the two, never piped tight, or the assembly cannot discharge properly.
4) What is the body of the Watts 0881378 air gap made of?
Cast iron. That matters for mechanical rooms and larger commercial installs where the fitting hangs off the relief valve and needs to take some abuse, and it is heavier than a plastic funnel drain, so support the drain piping rather than letting the air gap carry it.
5) Is the Watts 881378 air gap the same part as 0881378?
Same part. The manufacturer part number is 881378 and it is catalogued by Watts as 0881378 with a leading zero. Order either way and you get the cast iron air gap for 1-1/4 to 3 inch 009 and 909 assemblies.
How fast can I get the Watts 881378 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 Watts 881378 come with a warranty?
Absolutely. The Watts 881378 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 Watts 881378?
You can call, text, or email our expert support team for fast answers. We’re here to help with
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selection,
installation tips, and troubleshooting. Contact Us
Why buy the Watts 881378 from ZenSupply?
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