Emerson VSG & VSSG Troubleshooting Guide download pdf (Page 45)

VSG/VSSG • Compact Logix PLC Manual •Vilter/Emerson • 35391CL

Oil Mixing Valve

Various types of oil coolers can be used to maintain the oil injection temperature, usually either a water-cooled

shell-&-tube heat exchanger mounted locally or a remotely located air-cooled fan-coil unit. In either case, the oil

temperature control valve operates the same.

A two-way ball valve is located in the main oil line between the oil separator and the compressor. The oil cooler

is piped in parallel to the oil temperature control valve, which acts as a by-pass valve.

1.0 Installation & Position Indication

1.1 The ball valve is installed with the ball closed.

1.2 The actuator mounts on the ball valve stem. Flats on the ball valve stem indicate the position of the ball:

OPEN – stem flats are with the flow

CLOSED – stem flats are across the flow

1.3 On smaller valves, the ball valve stem flats are nearly hidden between the stem extension and the stem

lock nut. The locking tabs on the stem lock nut are across the flow.

1.4 The actuator position indicator stem flats are oriented in the same direction as the ball valve stem flats.

1.5 There is a mechanical position indicator on the top of the actuator cover.

NOTE: The oil temperature control valve comes from the vendor already assembled with the ball closed and the

actuator in the CLOSED position.

2.0 Control Action

2.1 The ball valve can rotate through a full 360° arc.

2.2 The actuator restricts the ball to a 90° arc of travel.

2.3 The actuator is powered (120V or 24V) all the time.

2.4 The position target signal from the compressor controller is a 4-20mA analog value.

2.5 There is no feedback position from the actuator.

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Emerson VSG & VSSG Troubleshooting Guide Page 45