Component Operation and Maintenance, Checks and Adjustments

7.1.2Electric Panel

The electric panel should be inspected for any loose electrical connections.

! WARNING

Be sure that power to the unit is shut down before attempting to tighten any fittings or connections.

Control Transformer and Fuses

The control system is divided into four (4) separate circuits. Fuses located on the transformer/fuse board individually protect the control voltage circuits. If any of the fuses are blown, first eliminate shorts, then use spare fuses supplied with unit. Use only type and size of fuse specified for your unit.

The small isolation transformer on the main control board supplies 24 volts to the electronics. The transformer is internally protected. If the internal protector opens, the transformer/fuse board must be replaced. Also check the control voltage fuse on the main control board before replacing the trans- former/fuse board.

Fan Safety Switch

For Deluxe units, the Fan Safety Switch is located in the low voltage compartment and consists of a diaphragm switch and interconnecting tubing to the blower scroll. The Fan Safety switch is wired directly to the control circuit to deactivate the unit and activate the alarm system if airflow is inter- rupted.

Firestat

The optional firestat is a bimetal operated sensing device with a Normally Closed switch. This device will shut down the entire unit when the inlet air temperature exceeds a preset point. It is connected between terminals 1 and 2 at plug P39.

Smoke Detector

The optional smoke detector power supply is located on the base of the upflow units, and at the top of downflow units. It is constantly sampling return air through a tube. No adjustments are required.

Water Detection Sensor

! CAUTION

Do not use near flammable liquids or for flammable liquid detection.

Liebert manufactures a variety of water-detection systems, including point, zone and cable systems. Follow the instructions supplied with your selected device for proper installation, adjustment and maintenance.

Remote Shutdown

A connection point is provided for customer-supplied remote shutdown devices. Terminals 37 and 38 on the terminal strip are jumpered when no remote shutdown device is installed. Refer to the unit’s electrical schematic and the unit’s installation manual.

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Emerson DE, VH Electric Panel, Control Transformer and Fuses, Fan Safety Switch, Firestat, Smoke Detector, Remote Shutdown

VE, DH, VH, DE specifications

Emerson is a well-known brand in the field of automation solutions, offering a range of products that cater to various industries. Among its diverse portfolio, Emerson’s products like DE (Digital Electronics), VH (Variable Frequency Drives), DH (Distributed Control Systems), and VE (Valve Positioners) stand out for their advanced features, cutting-edge technologies, and unique characteristics.

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