Engineered Controls 1/2″ MNPT Brass Hydrostatic Relief Valve 375 PSI LP Gas ONLY

SKU: 3129K

Weight	1.5 lbs
Dimensions	8 × 8 × 8 in

$110.86

In stock — available to order.

Sold individually. Each quantity ordered is one unit. Kits are one complete kit; products sold by length use the stated length unit.

Same-item volume pricing

Quantity	Unit price	Saving
1–4	$110.86	0%
5–9	$105.32	5%
10+	$99.77	10%

Estimate for this quantity before shipping. Tax display follows store settings. Existing cart quantities can increase the tier. Only one offer applies; a coupon replaces automatic pricing. For 20+ units, contact support for a quote.

Available to order.

Bulk quantity & quote

Quantity needed

Enter the total quantity you need. We will confirm availability and a quote before you order.

Need a firm ship date? Availability may include supplier stock. Confirm availability before ordering for time-sensitive work.

Engineered Controls 1/2" MNPT Brass Hydrostatic Relief Valve 375 PSI LP Gas ONLY

Specifications & product details

REGIONS SUPPLY BUYING GUIDE

Product details & buying advice

Where liquid can become trapped in a piping section, hydrostatic relief selection depends on that section’s service and pressure requirements.

Product type	Hydrostatic relief valves
Part / SKU	3129K

What to check before ordering

Compare the valve’s medium, pressure setting and connection with the protected section.
Have the system designer establish the installation point and discharge arrangement.
Use the replacement and fitting instructions supplied for the exact valve model.

Service reminder: Order for the equipment being protected. A hydrostatic line-relief valve is not a substitute for the tank’s relief valve.

Have gas-system installation and service completed by qualified personnel. Use the current instructions for the exact model and the requirements that apply at the installation location.

Product help & manufacturer resources

Explore this product guide · Shop this product group · Ask Regions Supply about this part

Overview

The Engineered Controls 3129K Hydrostatic Relief Valve is a compact, precision-engineered brass valve designed to protect piping and shut-off valves from the dangers of overpressure due to trapped liquid LP gas ONLY. This is especially critical in pipelines and hoses located between shut-off valves or in the side boss of RegO shut-off valves.

Its automatic reseating design ensures quick recovery after discharge, while the resilient seat disc maintains a “bubble-tight” seal for maximum leak prevention. The 3129K is available in both stainless steel and brass models, with configurations allowing direct vent piping attachment when required.

Specifications

Set
Pressure: 375 PSI
Height: 2-19/32"
Connection: 1/2" M. NPTWrench Hex: 1-1/8"Body
Material: BrassBenefits:Reliable overpressure protection for LP gas ONLYLong-lasting corrosion resistance from solid brass constructionCompact and easy-to-install design for tight piping spaces

Product details

Part / SKU	3129K

Package includes

Engineered Controls 1/2" MNPT Brass Hydrostatic Relief Valve 375 PSI LP Gas ONLY

Included components and any stated pack quantity are as described in this listing. Optional accessories shown separately are sold separately unless expressly included above.

Compatibility & part-number help

Match the manufacturer part number and equipment model to the listing. Check connection sizes, fuel type, pressure or capacity, voltage and dimensions where applicable. A similar appearance or part number alone does not confirm compatibility.

For help, send a parts inquiry with the part number, equipment model, label photos and quantity. Manufacturer documents and item-specific information, when supplied, are in the product details above.

Shipping & availability

Availability may include our inventory and supplier sources. Listed stock does not by itself confirm immediate dispatch. Ask us to confirm a ship date before ordering for time-sensitive work.

Shipping methods and charges appear at checkout where available. Freight, oversized and specially handled items may require a quote. See our Shipping Policy for processing periods, restrictions and delivery information.