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Manufacturer Resources
Product Specs
- Brand Name:
- Watts
- Brass Insert:
- No
- Fitting Name:
- Union
- Inlet Connection Size:
- 1/2 IN
- Inlet Connection Size Metric:
- 15 MM
- Inlet Connection Type:
- Quick Connect
- Inlet Material:
- Polysulfone
- Lead Free:
- Yes
- Maximum Working Pressure Bar:
- 17.2
- Maximum Working Pressure Psi:
- 250
- Maximum Working Temperature Celsius:
- 82
- Maximum Working Temperature Fahrenheit:
- 180
- Minimum Temperature Celsius:
- 24
- Minimum Temperature Fahrenheit:
- 75
- Model Number:
- 3515RB-1008
- O Ring Material:
- EPDM
- Outer Diameter:
- 1 1/8 IN
- Outlet Connection Size:
- 3/8 IN
- Outlet Connection Type:
- Quick Connect
- Outlet Material:
- Polysulfone
- Part Number:
- 650085
- Series:
- 3515RB
- Suitable For Gas Service:
- No
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- General Valve
- Product Finish:
- Polysulfone
- Product Material:
- Polysulfone
Watts 3515RB-1008 – Frequently Asked Questions
1) Can I use the Watts 3515RB-1008 plastic union on a hot water line?
Yes, within its rating. The connector is good to 180 F (82 C) at a maximum working pressure of 250 psi (17.2 bar), which covers normal domestic hot water supply. The published temperature range starts at 75 F (24 C), so it is specified for interior conditioned work, not exposed or freezing locations.
2) Can this Watts push-fit union be used on a gas line?
No. The 3515RB-1008 is not suitable for gas service. It is a water fitting only. For fuel gas you need a fitting specifically approved for gas, and substituting this one would be a code violation.
3) Is the Watts 3515RB-1008 lead free for potable water?
The 3515RB-1008 is listed lead free. The wetted parts are polysulfone with an EPDM O-ring, so there is no brass insert in this version at all, which is one of the ways it differs from the brass-insert variants in the same family.
4) How much clearance do I need behind a fixture for the Watts 3515RB reducing union?
Plan for a body outer diameter of 1-1/8 inch. That is the widest point of the fitting, so in a tight cabinet or a shallow wall cavity you need at least that much clear around the tube line, plus room to push the tube fully home into the joint.
5) What is the difference between a reducing union like the 3515RB-1008 and using a coupling with an adapter?
A reducing union does the size change and the joint in a single body, so you have one fitting and two push connections instead of a coupling plus a reducer and the extra joint between them. Fewer joints means fewer places to leak and less length in the run, which matters under a lavatory or behind an appliance where you have 1/2 inch CTS coming out of the wall and a 3/8 inch riser going to the fixture. The 3515RB-1008 covers that 1/2 to 3/8 step directly.
6) What exact part number do I order for the Watts 1/2 x 3/8 CTS plastic reducing union?
Order model 3515RB-1008 from the Watts 3515RB series. Watts also carries it under part number 650085. There is one configuration, so there are no finish or option choices to specify.
7) Is the 1/2 inch inlet on the Watts 3515RB-1008 the same as 15 mm?
Watts lists the 1/2 inch inlet as 15 mm metric equivalent. That is a nominal designation, not a licence to push a true metric 15 mm tube into it. The joint is cut for 1/2 inch CTS copper tube size, so stay with CTS tubing on that end.
How fast can I get the Watts 3515RB-1008 delivered?
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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 3515RB-1008 come with a warranty?
Absolutely. The Watts 3515RB-1008 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 3515RB-1008?
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