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Marshall Excelsior MER61148P 3/8" MNPT x 1/2" Female Flare High-Pressure Propane Hose 48 in. - USA Made, 350 PSI Rated

Marshall Excelsior MER61148P 48-inch high-pressure propane hose with 3/8 in. MNPT x 1/2 in. female flare fittings and crimped brass ends, Made in USA
Marshall Excelsior 3/8" MNPT x 1/2" Female Flare High-Pressure Propane Hose - 48"
 
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Part Number: MER61148P
Manufacturer: Marshall Excelsior

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Marshall Excelsior 350 PSI Rated Made in USA MER61148P High-Pressure Liquid Propane Hose -- 3/8 in. MNPT x 1/2 in. Female Flare, 48 Inches

A rugged, UL- and CGA-approved thermoplastic propane hose built for demanding RV liquid propane gas systems. With fully crimped brass fittings, thermal protection, and a 350 PSI working pressure rating, this Marshall Excelsior hose is engineered for reliability whether you are connecting a high-pressure regulator, a generator, or a propane appliance in a coach or fifth wheel.

Professional-Grade Propane Hose for RV and LP Gas Applications

The Marshall Excelsior MER61148P is a 48-inch high-pressure liquid propane hose designed for use in RV, commercial, and residential LP gas systems where a reliable, pressure-rated connection is required. The 3/8 in. male NPT thread on one end connects to regulators, valves, and manifolds, while the 1/2 in. female flare swivel end mates with standard POL-side or flare-fitting appliances and generators.

Unlike lower-grade rubber hoses, this hose uses a flexible thermoplastic inner tube with fully crimped brass end rings -- no hose clamps or field-assembly required. The crimp connections are factory-tested and provide a leak-free, pull-tested seal rated at 400 lbs. tensile strength. Thermal protection is integrated into the hose construction, adding a layer of safety in engine bays, under coaches, or near heat sources.

350 PSI Working Pressure

Rated for high-pressure liquid propane service -- well above typical low-pressure appliance hose ratings, suitable for generator and dual-stage regulator inlet connections.

Fully Crimped Brass Fittings

Both ends feature factory-crimped brass rings. No field assembly, no loose ferrules. The 1/2 in. female swivel end allows easy hand-tight alignment before wrenching.

UL and CGA Approved

Listed to Underwriters Laboratories standards and approved to CGA (Compressed Gas Association) specifications -- required for LP gas systems in many RV park and campground environments.

Made in USA

Manufactured by Marshall Excelsior, a Michigan-based company with decades of propane and LP gas equipment expertise. Backed by a limited 5-year manufacturer warranty.

Fitting Connections Explained

Getting the right hose means matching both ends to your application. Here is what each end on the MER61148P does:

  • 3/8 in. MNPT (Male National Pipe Thread): This is the fixed, non-rotating end. It threads directly into female NPT ports on high-pressure regulators, manual shutoff valves, propane manifolds, and generator fuel inlets. Apply thread sealant (PTFE tape rated for propane) to this end before installation.
  • 1/2 in. Female Flare Swivel: The rotating swivel end prevents the hose from twisting during connection. It accepts standard 1/2 in. male flare fittings (SAE 45-degree flare) found on many propane appliance inlets, POL adapters, and high-pressure regulator outlets.

If your application uses a different thread size or fitting type, Marshall Excelsior and most propane distributors offer brass adapter fittings to bridge the gap -- the hose itself does not include adapters.

Swivel End Advantage: The 1/2 in. female flare end rotates freely, making it much easier to connect in tight under-coach or compartment locations without kinking the hose or cross-threading the fitting.

Common RV Applications

  • Connecting a high-pressure two-stage regulator outlet to a generator propane inlet
  • Linking a manual propane shutoff valve to an external generator or BBQ quick-connect
  • Replacing worn or cracked OEM high-pressure hoses on Class A, Class C, fifth wheels, and travel trailers
  • Custom LP gas plumbing in cargo trailers, food trucks, and converted vans with propane systems
  • Secondary fuel supply lines in dual-fuel or extended-range propane setups
High-Pressure vs. Low-Pressure Hose: This is a high-pressure hose rated at 350 PSI -- it is designed for use between the propane tank and the first-stage or two-stage regulator, or between a high-pressure regulator and a generator. It is not a low-pressure appliance hose for the 11 in. WC (water column) side of a regulator feeding a stove or furnace. Make sure your application actually requires high-pressure hose before purchasing.

Installation Tips

For a Leak-Free Installation:
  • Apply yellow PTFE tape (gas-rated, not standard white plumbing tape) to the 3/8 in. MNPT threads before installation. Wrap clockwise 2-3 times.
  • Hand-tighten the 1/2 in. female flare swivel first to confirm alignment, then snug with a wrench -- do not overtighten flare fittings.
  • After connecting, perform a leak test using a propane-safe leak detection solution or soapy water. Do not use an open flame to check for leaks.
  • Route the hose away from exhaust pipes, generator mufflers, and sharp edges. Use grommets or conduit where the hose passes through sheet metal.
  • The 48 in. length provides enough slack for most compartment installations. Avoid sharp bends tighter than the hose's natural flex radius.

Warranty

This hose is covered by Marshall Excelsior's limited 5-year manufacturer warranty against defects in materials and workmanship under normal use conditions. Warranty does not cover damage from misuse, improper installation, or use outside the rated pressure and temperature range.

Product Specifications

ManufacturerMarshall Excelsior
Part NumberMER61148P
SKU06-3897
UPC815505014120
Country of OriginMade in USA
WarrantyLimited 5-Year Manufacturer Warranty

Hose Dimensions

Total Hose Length48 inches
Hose Outside Diameter3/8 inch
Weight1 lb.

Fitting Specifications

End 1 (Fixed)3/8 in. MNPT (Male National Pipe Thread)
End 2 (Swivel)1/2 in. Female Flare (SAE 45-deg)
Fitting MaterialBrass, fully crimped
Swivel EndYes -- female end rotates for easy installation

Pressure and Safety Ratings

Working Pressure350 PSI
Pull Test Rating400 lbs.
Gas TypeLiquid Propane (LP) / LPG
Hose MaterialFlexible thermoplastic with thermal protection
UL ListedYes
CGA ApprovedYes

What Is Included

Hose Assembly1 x 48 in. propane hose with factory-crimped ends
AdaptersNot included
PTFE Thread TapeNot included
Important Information -- Read Before Installing
  • This is a HIGH-PRESSURE propane hose rated at 350 PSI. Confirm your application requires high-pressure hose before installation. Do not use this hose on the low-pressure (appliance) side of a regulator.
  • Use only with propane (LPG) gas. Not rated for natural gas, compressed air, or other gas types.
  • Always use gas-rated (yellow) PTFE tape or an approved pipe thread sealant on the 3/8 in. MNPT end. Standard white plumbing PTFE tape is not rated for LP gas service.
  • Perform a leak test with an approved leak detection solution after every installation. Never use an open flame to check for leaks.
  • Do not exceed 350 PSI working pressure. Do not use a hose that shows any signs of cracking, abrasion, kinking, or damage.
  • Route hose away from heat sources including exhaust manifolds and generator mufflers. Thermal protection is included but not a substitute for proper routing.
  • Installation must comply with NFPA 58 (Liquefied Petroleum Gas Code) and all applicable local codes. When in doubt, consult a certified LP gas technician.
  • Adapters are NOT included. Purchase separately if your application requires a different thread size or fitting type.


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