Installation

If compressed air is applied at Control Port 4, the control piston moves downwards, the outlet is closed, the inlet opened and the Reservoir pressure at Port 1 is directed to the Delivery Port 2 corresponding to the control pressure.

The inlet is closed and the outlet remains closed when the pressure at the Port 2 (this pressure is also applied to the underside of control piston) is equal to the pressure at Port 4. A termination setting is provided. Each change in pressure at Port 4 results in a change in pressure at Port 2. lf air is allowed to escape at Port 4, then the inlet is closed, the outlet opened and air escapes from Port 2 via Exhaust Port 3. 

The stud bolts provided are used for mounting the valve. The vent must face downwards. Testing If defects are found during brake tests, brake inspections or when driving, the relay valve must be thoroughly inspected and replaced if necessary. Checking check function and for leaks.