Description

Overview

DC-4 double check valve 3/8 ports provides automatic selection between two air supplies feeding one air brake circuit. It directs the higher pressure source to the delivery port so trailer brake control stays stable. Additionally, the internal shuttle design limits backflow into the lower pressure circuit and helps protect upstream components. As a result, this valve suits heavy vehicle and trailer applications where reliability matters.

Features

This double check valve 3/8 ports design offers simple, robust operation for demanding air brake systems. Firstly, the shuttle mechanism responds directly to pressure differences with no external power or controls. Secondly, the compact body suits tight mounting spaces on trailers and prime movers. Additionally, the recommended horizontal mounting orientation helps the shuttle move freely. Finally, three NPT female ports provide straightforward plumbing into existing air lines.

Specifications and Materials

This DC-4 pattern valve is used when a single function or component must receive air from, or be controlled by, the higher of two pressure sources. The internal disc or shuttle moves in response to the higher supply and passes that source to the delivery port. Model designation is DC-4 with 3/8″ NPT female ports and three ports in total, and installation best practice is horizontal shuttle operation to maintain consistent movement. Part number: AB8369AP. For more technical detail on double check valve operation, see this manufacturer technical guide

Compatibility and Fitment

This cross-reference listing means this valve is a suitable replacement for the part numbers and applications shown. Some changes in air line plumbing may be required. 278614, 20QE283, 20QE283R, 286414, 12215, 1650700, KN25061, 810788, 814316, E860944, 49900067, RKN25060, P21809B, 103099, 217698, 229521, 287181, 287628, 654434, 29491892, 140103, 550007, 2R0619, 2155224, 3827694, E9220646, M1567186, 12P183, 34639, 3468, 39460301-2, 1041229009, 1037878, 350166, 9220646, F020344, 18A0296, 18A296, C1TT2575A, D5A2K119AA, D5TZ2K119A, 825448, AWA6499SP09, V2A8861, 10130001, 10130390, 207921, 37207921, 10500586, GTA278614, KN25060, KN25080, 36Z11, H278614, 42042312, K278614, TR9335, 745-278614, X9220646, WZ278614, 284999C91, 764368C92, BAN278614, NC10802, 2257FX, 1733201806, 17332B018, 2601727, 340546, 801206, 9340546, K29520006, 30879031P, 550039, 1019116, 1577392, 3081438, 12900013, 532482, KN25110, N20966F, 283321, 289296

Compliance and Safety

In a correctly designed system, this DC-4 style valve supports compliance with recognised air brake practices by keeping the controlled circuit supplied from the higher available pressure. Additionally, using a dedicated double check valve for this function helps installers avoid improvised plumbing that could compromise safety. Always follow current workshop procedures and torque recommendations when assembling fittings, and pressure test the circuit after installation.

Trailer Applications

Trailer builders and repairers use this double check valve 3/8 ports design where a single service must draw from tractor and trailer supplies or primary and secondary circuits. For example, it can feed signal air to relay valves, spring brake release circuits, or auxiliary functions that must operate from whichever supply is higher. Furthermore, the compact body allows mounting close to manifolds or valve clusters, which helps reduce line length and potential leak points.

Cross-reference and Suitability

This part cross-references to or suits the following equivalent part numbers and compatible alternatives:

Always confirm the existing installation and line routing on the vehicle before finalising replacement with this valve.

Why Choose ICS Trailers

ICS Trailers focuses on heavy vehicle and trailer braking components, so you get parts that suit real workshop conditions. In addition, our team understands how double check valves integrate with modern air systems and can assist with product selection. Moreover, we maintain local stock levels to help reduce downtime on fleets and individual trailers. Browse Air Brake Parts at ICS Trailers