Yellow Jacket 49138 Pressure Gauge – 3-1/8″ Dial, Blue, Class 1 Low-Side Gauge, 0–250 PSI with -30 inHg Vacuum Scale for HVAC/R Systems

Yellow Jacket 49138 Pressure Gauge – 3-1/8″ Dial, Blue, Class 1 Low-Side Gauge, 0–250 PSI with -30 inHg Vacuum Scale for HVAC/R Systems

Condition: Used. Cosmetic wear consistent with use including lens scuffs and bezel marks; dial is intact and needle motion is smooth. Vacuum and pressure scales are legible.

The Yellow Jacket 49138 is a 3-1/8″ Class 1 precision pressure gauge used for low-side (suction) pressure and vacuum measurements in HVAC/R systems. Featuring a blue dial face, this gauge measures from -30 inHg (vacuum) to 250 PSI, making it ideal for use with refrigerants like R-22, R-134a, R-404A, and R-410A in both residential and commercial systems. It is compatible with most analog manifold sets and designed to deliver ±1% full-scale accuracy, making it suitable for critical service, troubleshooting, and system performance verification.
This gauge is part of Yellow Jacket’s service-proven analog manifold family and is designed for direct replacement on most manifold blocks using a 1/8″ NPT bottom mount connection.

🔧 Features:
Model: 49138
Dial Size: 3-1/8 inches (80 mm)
Dial Color: Blue (low side)
Pressure Range: -30 inHg to +250 PSI
Accuracy: ANSI Class 1 (±1% full scale)
Connection: 1/8″ NPT (typically bottom mount)
Lens: Clear polycarbonate
Body: Steel housing with impact-resistant bezel
Use: For low-pressure/vacuum measurement on HVAC/R systems
Refrigerant Compatibility: Suitable for R-22, R-134a, R-410A, R-404A, and more

🏭 Applications:
Air conditioner and heat pump service
Refrigerant recovery and charging
Deep vacuum pulls and system evacuation checks
Chiller and commercial refrigeration systems
Automotive A/C diagnostics (with appropriate manifold set)
Paired with high-side red gauge (e.g., Yellow Jacket 49137)

🔄 Cross-Referenced Models:
Yellow Jacket 49136 – Similar pressure range, different scale layout
Robinair 42014 – Low-side gauge with similar range and face
CPS GRL-250B – 3-1/8″ blue low-pressure HVAC gauge
JB Industries M2-825L – Class 1, blue gauge, same pressure range
Fieldpiece GLR3 – Blue analog gauge for low-side refrigerant pressure

📌 Comparable Products:
Mastercool 59161-B – Low-side blue gauge with same pressure range
Imperial 416-BC – Class 1 blue gauge for manifold kits
Supco VG64 analog gauge – Similar low-side pressure functionality
CPS Products Pro-Set Gauge – Blue 1/8″ NPT HVAC service gauge

🧩 Part of Larger Systems:
This gauge is typically installed on:
Yellow Jacket 2-valve and 4-valve manifold gauge sets
Universal HVAC/R charging manifolds with 3-1/8″ face compatibility
Custom diagnostic stations for refrigerant pressure measurement
Often paired with Yellow Jacket 49137 (red high-side gauge)
Used in conjunction with:
Vacuum pumps
Refrigerant recovery units
Charging hoses and service ports on A/C systems

⚠️ Trademark Disclaimer:
All product names, logos, brands, and other trademarks mentioned are the property of their respective owners. These names are used solely for identification purposes and do not imply endorsement or affiliation.

Related:
low-side refrigerant pressure gauge
blue vacuum and pressure HVAC gauge
analog suction pressure gauge 3-1/8”
Yellow Jacket 49138 replacement gauge
0–250 PSI Class 1 HVAC manifold gauge
HVAC gauge with -30 inHg vacuum scale

Common Requests:
“Used low-pressure blue gauge for Yellow Jacket manifold”
“49138 vacuum and pressure gauge specs”
“HVAC/R low-side analog gauge 3-1/8 inch”
“How to replace Yellow Jacket 49138 gauge”
“What gauge fits R-134a and R-410A low pressure side?”

All product names, trademarks, and registered trademarks are the property of their respective owners. Use of these names does not imply any affiliation or endorsement.

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