278615-G | Double Check Valve (Diaphragm Type DC-4 Style)

278615 DOUBLE CHECK VALVE – 3/8" NPT, NON-POSITION-SENSITIVE, DIAPHRAGM TYPE

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PART NUMBER(S):
Fleet Products: 278615, 278615-G
OE: 278615, DC-4, N20954A, 12378837-001
Automann: 170.278615

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DESCRIPTION:

Model: Double Check Valve – Diaphragm Type
Vehicles: Compatible with heavy-duty trucks, buses, and trailers
• Inlet Ports: (2) @ 3/8" NPT (female)
• Delivery Port: (1) @ 3/8" NPT (female)
• Optional Alternate Ports: (2) @ 1/4" NPT (female) – variant dependent
• Mounting: Universal orientation; not position sensitive
• Actuation Type: Internal diaphragm valve
• Function: Automatically selects the higher of two air pressure sources and directs it to a common delivery port, preventing backflow between sources
• Interchangeability: Direct replacement for shuttle or ball-type check valves
• Unique Features: Non-position-sensitive mounting, integral diaphragm design, engineered for low-leakage and fast response
• Housing Material: Aluminum body with internal diaphragm
• Dimensions: Length – 2.59" (65.8 mm), Width – 2.12" (53.8 mm), Height – 2.66" (67.6 mm)
• Weight: Approx. 0.3 lbs
• Operating Temperature: -40°F to +200°F (-40°C to +93°C)
• System Fitment: For use in air brake systems where pressure priority control between two sources is required
• Compliance: FMVSS 121 compliant valve performance

Applications:
Used extensively in commercial truck, bus, and trailer air brake systems to allow a single system to be supplied by the higher pressure source of two, while blocking reverse flow. Often used in emergency/secondary supply functions or combined brake control logic systems.

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CROSS-REFERENCE(S):

278615, 278615-G, KN25060, H278615, DC-4, DC4, N20954A, 1779P1005, 8935030544, 9340990030, 9340990140, A261H75, A3495V74, EBN278615X, RKN25060, RMPN20945A, 217698, 277988, 278614, 283321, 286414, 287181, 287628, 288334, 289547, S117726, 51285502541285502, 350180, 8A1388, C4TS2575B, D5TA2K119AA, D5TZ2K119A, 825388, ALA5344, MBW278615, X17457, 15536221, 2099294, 2485247, 78037062, 86683301, 7926001228, 201129AA, KSV4040734, 13QE15, 20QE2222R, 20QE283, 278615N, 278615BXW, 278615P, 275858, 285543, BEN-278615, BEN-278615N, BW275858, BW278615, BW278615N, BW285543, BW288334, BX275858, BX278615, BX278615N, BX285543, BX288334, FC278615, R955278615, R955278615N, R955278615X, TDAR955278615N, 170.278615, 745278615N, 1676719C, BAN278615N, BX278615N, ZAC27615, 3081439, 724040012, 745-278615N, 6D-3781, 6D3781, 14558, TV278615, TV278915, AV278615, E-BN278615N, BER-278615, S-16923, S16923, WA278615, K278615, 4R-15-2, 0587-278615P, 278615P, M1083 and M1078 Series LMTV and FMTV Military Trucks 4820-360-6152, 48203606152

A cross-reference listing means this part may be a compatible replacement for these part numbers based on OEM or distributor data.

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IMPORTANT INSTALLATION NOTES:

✔ May be mounted in any orientation; no directional or positional constraints
✔ Ensure all port threads are clean and properly sealed with DOT-approved compound
✔ Verify correct pressure source lines are connected to inlets A and B
✔ Confirm leak-free installation and correct pressure priority during functional test
✔ Replace with diaphragm-type only if system requires internal diaphragm sealing and non-shuttle behavior

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