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Manufacturer Resources
Product Specs
- Body Material:
- Lead Free Brass
- Buy American Act Compliant:
- No
- Inlet Connection Size:
- 1/2 IN
- Inlet Connection Type:
- Male Threaded
- Lead Free:
- Yes
- Maximum Temperature Fahrenheit:
- 250
- Maximum Working Pressure Psi:
- 15
- Protection Type:
- Pressure
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
- Brand Name:
- Watts
Watts LFN36M1 1/2 – Frequently Asked Questions
1) What size and type of connection does the Watts LFN36M1 1/2 vacuum relief valve have?
It threads in with a 1/2 inch male NPT inlet, so it screws directly into a 1/2 inch female tapping on a water heater, tank, or fitting. No adapter is needed if the tapping is 1/2 inch FNPT; if the port is larger you will need a reducing bushing.
2) Is the Watts LFN36M1 1/2 relief valve safe for potable water lines?
Yes. The body is lead free brass and the valve is flagged lead free, which is what a plumbing inspector looks for on a domestic hot or cold water installation.
3) Can I use the Watts LFN36M1 1/2 as the T and P safety valve on a water heater?
No. This is a vacuum relief valve, not a temperature and pressure relief valve. It breaks vacuum by letting air in; it will not discharge an over-pressurized or overheated tank. Keep the ASME or AGA rated T and P valve in its own tapping and use this one on the cold side to prevent siphoning.
4) Will the Watts LFN36M1 1/2 meet Buy American requirements on a federal or public project?
No. The LFN36M1 1/2 is flagged as not Buy American Act compliant, so for a federal job carrying BAA or Build America requirements you will need to source a domestically manufactured vacuum relief valve instead.
5) What is a vacuum relief valve for, and do I need one on my water heater?
A vacuum relief valve admits air into a tank or line when the internal pressure drops below atmospheric, which stops the tank from siphoning empty or collapsing when supply is shut off or a line below the tank is drained. Many codes require one on the cold inlet of a water heater or storage tank fed from above. It is a different device from a T and P relief valve, which dumps excess pressure and temperature. Most heaters need both; this one handles the vacuum side only.
6) Does the LFN36M1 1/2 hold up on a 180 degree hot water storage system?
Yes, temperature is not the constraint. The valve is good to 250 degrees F, well above any domestic hot water setpoint. Watch the 15 psi working pressure limit instead, since that is the spec that rules most installations in or out.
7) Does the Watts LFN36M1 1/2 come with anything to keep debris out of the opening?
A protective cap ships on the valve. It keeps dirt and insects out of the vent opening while still letting the valve draw air when a vacuum forms. Leave it in place after install rather than discarding it.
8) What part number do I order for the 1/2 inch Watts lead free vacuum relief valve?
Order Watts model LFN36M1 1/2. The LF prefix marks the lead free brass version, and the 1/2 designates the 1/2 inch male NPT inlet.
How fast can I get the Watts LFN36M1 1/2 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 LFN36M1 1/2 come with a warranty?
Absolutely. The Watts LFN36M1 1/2 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 LFN36M1 1/2?
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