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Reliance 3/4 in. MNPT Brass Relief Valve

Made in America

Support American manufacturers + independent hardware retailers in one purchase.

Keeps your water heater tank from over-pressurizing or overheating - lead-free brass, rated to 150 PSI and 210°F.
Reliance MPN 100108280 In Stock & Ready to Ship
$18.99
Free shipping on orders over $75
Ships within 24 hours · most orders arrive in about 2 business days

About Product Overview

This Reliance relief valve protects your water heater from dangerous buildups in pressure and temperature, shutting off flow before tank pressure exceeds safe limits. The 3/4" brass body threads in with a standard MNPT connection, and the lead-free construction meets modern plumbing codes for potable water systems. It's a fixed-setting valve, not adjustable, so it's built to factory spec and ready to install as a direct replacement part.

  • Body Material: Brass
  • End 1 Type: MNPT, 3/4" size
  • Maximum Pressure: 150 PSI
  • Maximum Temperature: 210°F
  • Lead-Free construction
  • Made in USA

The Details Specifications

Brand Reliance
Model / MPN 100108280
UPC 020363104597
Weight 1 lbs
Country of Origin USA
Safety Data Sheet (SDS) Manufacturer documentation · opens in new tab
Price check

Go ahead. Check.

You're going to price-check us against Amazon, Home Depot, and Lowe's. Everybody does. Good — open all three tabs. We'll wait. Then look hard at what you're actually being handed over there.

On Amazon, start with these four questions before you click buy.

01

Who's actually selling it

The brand name is on the listing. A different company is in the seller field. Those aren't the same thing, and the second one is who you're buying from.

02

Whether the warranty survives

Most manufacturers only honor a warranty when the unit came through an authorized dealer. We're authorized for Reliance. A third-party marketplace seller usually isn't.

03

Where the box came from

Gray-market stock, returns repackaged as new, and outright fakes move through marketplaces constantly. It all looks identical in the photo. It stops looking identical when it fails.

04

Who you call when it breaks

Ours is a phone number with a person behind it who has held this product. M–F, 6 AM – 5 PM Pacific. (866) 469-8556

The big boxes don't care if your hardware store survives.

Amazon, Home Depot, and Lowe's are built to pull every hardware dollar out of your town. When the local shop can't keep the lights on, the counter where somebody actually knew which part you needed goes with it. We're built the other way: real brands so you're never stuck on a marketplace, and a straight answer to buy it down the street when that's the better call. Support independent hardware — it doesn't restock itself.

Why we tell you to shop local
Authorized dealer · Reliance

Or skip the tabs entirely and buy it down the street. Find a store near you →

Shop Local · Support Independent

Every order helps keep your local hardware store on the corner.

Why we built NHG
You might find it for less locally. Independent retailers often offer competitive pricing — some products are even cheaper in-store than online.
Real expert advice — not search results. Independent hardware staff know their inventory and the local conditions you're working in.
Keep the neighborhood working. Every dollar spent at an independent retailer returns roughly 3x more to your local economy than at a national chain.

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