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    David Richardson/NCI
    Interior Hvac Diagram
    Interior Hvac Diagram
    Interior Hvac Diagram
    Interior Hvac Diagram
    Interior Hvac Diagram
    David Richardson/NCI
    If you know what to look for, a visual inspection provides clues to unsafe operation. It's never good for one package unit to exhaust into the economizer of an adjacent unit.
    If you know what to look for, a visual inspection provides clues to unsafe operation. It's never good for one package unit to exhaust into the economizer of an adjacent unit.
    If you know what to look for, a visual inspection provides clues to unsafe operation. It's never good for one package unit to exhaust into the economizer of an adjacent unit.
    If you know what to look for, a visual inspection provides clues to unsafe operation. It's never good for one package unit to exhaust into the economizer of an adjacent unit.
    If you know what to look for, a visual inspection provides clues to unsafe operation. It's never good for one package unit to exhaust into the economizer of an adjacent unit.
    National Comfort Institute
    Before you jump on the heat pump bashing bandwagon, look at your duct installation practices first.
    Before you jump on the heat pump bashing bandwagon, look at your duct installation practices first.
    Before you jump on the heat pump bashing bandwagon, look at your duct installation practices first.
    Before you jump on the heat pump bashing bandwagon, look at your duct installation practices first.
    Before you jump on the heat pump bashing bandwagon, look at your duct installation practices first.
    Contracting Business/Kelly L Faloon
    Ahr2023 Succession
    Ahr2023 Succession
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    Contracting Business/Kelly L Faloon
    Ahr2023 Women
    Ahr2023 Women
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    Ahr2023 Women
    Contracting Business/Kelly L Faloon
    Ahr2023 Nate
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    Contractingbusiness 2114 Cb0911 Service Tip
    Contractingbusiness 2114 Cb0911 Service Tip
    Contractingbusiness 2114 Cb0911 Service Tip
    Contractingbusiness 2114 Cb0911 Service Tip
    Contractingbusiness 2114 Cb0911 Service Tip

    Service Tip

    Sept. 1, 2011
    Q: Explain the parts to a service valve. A: The typical service valve is composed of four essential parts: line connection, valve stem, service opening or gauge port, and compressor connection.

    Service Valves

    Q: Explain the parts to a service valve.

    A: The typical service valve is composed of four essential parts: line connection, valve stem, service opening or gauge port, and compressor connection.

    Typically, the service valve has a common connection that's always open. When the valve is back-seated (the stem is all the way out), the gauge port is closed and the valve is open, allowing refrigerant to flow through the system. If the valve is front-seated (stem all the way in), the gauge port is open to the compressor connection and the refrigerant line (suction or discharge) connection is closed.

    In order to read the pressure while the valve is open, the valve should be back-seated, then turned once or twice to slightly open all three connections: the gauge port, line, and compressor. This allows both the compressor and refrigerant line to be open and vapor pressure to flow through. At the gauge port, you can check system pressure and charge or reclaim refrigerant.

    When brazing a service valve: make sure the valve is mid-seated before brazing. The heat from brazing a fully-front-seated or back-seated valve can cause the button of the valve stem (inside the valve) to "weld" to the seating area on the inside of the body of the valve. A technique called "wet ragging" can also help. Soak a rag in cold water and wrap it around the service valve before brazing. Make sure water doesn’t enter the valve.

    Copyright 2008 Emerson Climate Technologies, Inc.
    All rights reserved. Used by permission.