TROUBLESHOOTING PROCEDURE

For CAC Air Handlers With Remote Thermostat Controls

WARNING

All service should be performed by a qualified service technician. Before re- moving access panels or control covers to expose moving parts of non-insulate live electrical components for service, disconnect all high Volt power supplies to both the indoor unit and outdoor unit.

Figure 1

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Failure to do so could result in physical

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injury and/or electrical shock.

When troubleshooting the indoor unit, please refer to the wiring diagram that is supplied with the equipment. It is located on the back of the control access panel. If you are unable to locate the wiring dia- gram please feel free to call the factory technical service line at (800) 228-9364 and one can be faxed or mailed. Please have the full model and serial number available prior to calling.

EMI America Series evaporators are de- signed to operate with EMI America Se- ries condensers. The evaporator (indoor unit) and condenser (outdoor unit) are to be independently connected to the electri- cal service panel and protected by sepa- rate time delay fuse or HACR breakers. (See the unit name plate for the correct breaker type and size). The indoor and outdoor units are also connected to each other via a 24V interconnect wiring. A transformer provides the low Volt power source for the controls. The number of low Volt interconnect conductors will be three to five depending on heating options and or thermostat selection. Interconnect wire should be at least 18awg. Refer to the unit wiring diagram for the interconnect diagram that matches your system.

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Power Supply Check

Power supply check

When troubleshooting any EMI product, it is important to first check the rating plate for proper field Voltage and breaker size. Secondly using a Voltmeter check the incoming power supply to see that it agrees with the rating plate. The incoming power should not exceed the nameplate Voltage. Also, the incoming power should not be below the minimum Voltage stated on the rating plate (197V for units rated 208/230V).

A check for low Voltage power should also be made. By placing a Voltmeter across low Volt terminals “R” and “C” at the indoor unit, there should be a reading of 24V.

CAC Cassette Evaporator

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EMI CAC manual Troubleshooting Procedure, Power Supply Check

CAC specifications

EMI CAC, or Electromagnetic Interference Common-mode Current, is a critical concern in electronic device design and operation. It refers to the unwanted electromagnetic energy that can disrupt the normal functioning of electronic circuits, particularly in complex systems. EMI can arise from various sources, including power lines, radio frequency transmitters, and even other components within the same device.

One of the main features of EMI CAC is its dual nature. It can be both a source of interference and a metric to assess the integrity of electronic systems. The impacts of EMI are far-reaching, affecting communication signals, power supply reliability, and overall device performance. As technology progresses and devices become more compact, the likelihood of EMI issues increases, making it essential for engineers to develop effective solutions.

Several technologies are employed to mitigate EMI CAC in electronic systems. Shielding is one of the most common methods, involving the use of conductive materials to block electromagnetic fields. This can take the form of metal enclosures or coatings that prevent the escape of emissions. Another strategy involves the use of filters, such as ferrite beads and capacitors, which can suppress common-mode currents before they enter the sensitive parts of a circuit.

The characteristics of EMI CAC vary depending on several factors, including frequency, amplitude, and the specific environment in which the electronic devices operate. High-frequency EMI is particularly challenging due to its ability to penetrate enclosures and disrupt signals. Additionally, common-mode noise can often appear in differential signals, exacerbating the situation and making detection more difficult.

Achieving EMC (Electromagnetic Compatibility) is a major goal for designers dealing with EMI CAC. This involves not only reducing emissions from devices but also improving their immunity to external sources of interference. Effective grounding techniques and careful layout planning are crucial in minimizing EMI effects.

In summary, EMI CAC represents a significant challenge in modern electronics, with a need for advanced solutions to ensure device performance and reliability. By understanding its features, employing effective technologies for mitigation, and addressing its characteristics, engineers can create robust designs that thrive in the increasingly complex electromagnetic landscape of today’s technological world.