Taylor TW-357 manual Removing/Installing the Solenoid Valve, Ohms to 18 K ohms

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TW-357 REV E

• Move the sensor up or down so that the appropriate numbers of sensors are in liquid (read “L”).

• Get back to the KRYOS main screen and the level indicated should match the physically measured reading.

The Sensor Offset, the Start Fill and the Stop Fill can all be set through the KRYOS menu system (MENU, 2).

Removing/Installing the Solenoid Valve

Disconnect only the solenoid valve lead connection from the back of controller board.

To remove the solenoid valve, loosen the compression fitting that connects the plumbing tubing to fill tube. Unscrew the two (2) mounting screws that hold the solenoid valve to the solenoid bracket. Then remove the solenoid valve and its associated plumbing. Disconnect the plumbing from the inlet and outlet side of the solenoid valve.

To install a new solenoid valve, attach the connecting plumbing to the inlet and outlet connections of the valve using Teflon tape. Attach the compression fitting to the fill tube first and then connect the compression fitting to the elbow that is connected to the outlet side of the solenoid valve. Position the solenoid valve onto the solenoid valve bracket and tighten the two (2) mounting screws. Attach the solenoid valve lead connection to the controller board.

NOTE:

After disconnecting the solenoid valve leads do not pull on wire. The wires are tied and spiral wrapped together.

Controller Electrical Tests

If a controller is removed from the refrigerator for service, the liquid refrigerant level must be maintained manually to protect stored product. The fill solenoid valve will be inoperative with the controller removed. A flexible fill line terminated with a phase separator may be used periodically through the open refrigerator lid to conduct manual fill operations until automatic operation is restored.

Sensor Probes. The sensor probes used to detect liquid level by Taylor-Wharton controllers are temperature- sensitive resistors called “thermistors.” Their resistance to electrical current flow changes greatly with their temperature. The resistance of a typical thermistor used in these controllers varies with its temperature as follows:

• At Room Temperature

2 ohms to 10 ohms

• In Cold Nitrogen Gas

8 K ohms to 18 K ohms

• In Liquid Nitrogen

18 K ohms to 35K ohms

Controller Logic. The liquid level controllers read the values of the sensors as indications of liquid level. The function of a sensor, and its value, are interpreted by solid-state logic circuitry to set normal operating, fill, fill termination, and alarm conditions. In addition, the refrigerator temperature is monitored and an alarm is triggered if the temperature raises above a pre-determined point. The following values will be interpreted by a controller as cause for a logic change – either an alarm, or in some cases, a fill or fill termination action.

From cold gas to liquid

Resistance greater than 22K ohms.

From liquid to cold gas

Resistance less than 16K ohms.

Defective Sensor

Resistance greater than 50K ohms, or less that 5 ohms.

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Contents Labs TW-357 REV E Table of Contents InstallationExtreme Cold Cover Eyes and Exposed Skin Safety Precautions for Liquid NitrogenKeep Equipment Area Well Ventilated Liquid Nitrogen SystemDispose of Waste Liquid Nitrogen Safely Freight Damage PrecautionsElectrical Text Format Notation General InformationLabs Cryostorage Specifications Kryos Specifications Unpacking and Inspection InstallationLiquid Nitrogen Supply Connection Repackaging for ShipmentKryos Control Field Installation Power Supply ConnectionInitial Fill OperationControl Components Sensor AssemblyInterface Panel Battery Backup Lid SwitchRemote Alarm Solenoid ValveOperating Parameters Liquid Phase StorageThermocouple Positioning Adding an Inventory Control SystemInventory Control System Layouts Labs Cryostorage System Racks are not Square Orientation is ImportantLABS-80K LABS-40K Fenwal 4R59953 Blood Bag Rack Arrangements Fenwal 4R5462 9955 Blood Bag Rack Arrangements Control Operation PowerIntroduction Normal Fill CycleMenu System Main Display ScreenHigh Temperature 4.1 Valve Open Calibrate Temperature Temperature Thermocouple SelectTest Temperature System Help ScreensSensor Type Alarms and Error ConditionsTest Alarms System AlarmsLogging Dump Logs Error LogsSystem Logs Temperature LogsErase Logs SecurityControl By Temperature Lid Switch SetupTemperature Control Settings Control TemperatureUser Access Logs Serial Communications and RS-232 SettingsTime and Date Set Freeze-Guard Options Control RangeValve Monitoring Valve Open DurationSolenoid Valve Control On Battery Backup VersionDisplay Brightness About this ControlInterface Software Battery LifeStrainer Cleaning Instructions MaintenanceDefrosting Your LAB-Series CryoStorage System Cleaning Your Taylor-Wharton CryoStorage System Making Adjustments to the Labs Kryos Sensor Assembly Kryos Kryos V9.0 & Kryos V9.0B Level Readings Default Start Fill / Stop Fill Default Auto DefogOffset Value Units of measureOhms to 18 K ohms Removing/Installing the Solenoid ValvePin View Schematics Sensor Plug SchematicPlumbing Assembly Labs Plumbing AssemblySymptoms TroubleshootingController Will Not Turn on Indicates High Liquid LevelIndicates Low LN2 Supply Temperature reading 10 to 20 degrees warmIndicates Open Sensor QCF Quick Chill Feature Will Not Operate Lid Open AlarmFill Solenoid Cycles On and Off Fill Solenoid Makes Humming NoisePower Failure Alarm Defog Feature Will Not OperatePush Buttons Will Not Respond Liquid Level Readout is IncorrectFactory Settings Level Controller Electrical/Mechanical Parts80K/40K/20K Replacement PartsTaylor-Wharton Technical Services. Phone 800-898-2657 Fax Harsco Corporation