Frequently Asked Questions, How long will the fan run?

TROUBLESHOOTING PROCEDURE Continued

Frequently Asked Questions

Q:The system has just been installed using an EMI indoor unit and a non-EMI con- denser and the unit will not operate.

A:The CAC air handlers is manufactured with a low Volt transformer installed. EMI outdoor condensers are manufac- tured without a low Volt transformer. When connecting an EMI evaporator to a non-EMI condenser, check to ensure that there is a 24V control transformer in either in the indoor unit or outdoor unit. Only one transformer is required. If both the indoor unit and outdoor unit contain a transformer, one must be re- mover from the system.

Q:The condenser will not start although the indoor unit appears normal. What should I do?

A:At the indoor thermostat, make sure that the control is in cooling and the setpoint temperature is below room temperature. Next, using a Volt meter, check for 24V across the yellow (Y) and brown (C) wires. If 24V is present then check for wiring breaks or improp- er connections between the indoor and outdoor units.

A:Some EMI condensers are equipped with a manual reset high-pressure switch. It is located on the high side of the system usually on the discharge line of the compressor. To reset, sim- ply push the red button in. If the switch was tripped there will be a “click” when it resets.

A:CAC air handlers are equipped with an internal condensate pump with a high level safety switch. If the condensate reaches a critical level or if power is lost to the indoor unit, the safety cir- cuit will open and low Volt power to the

condenser (terminal “Y1”) will be re- moved. The condensate pump should be checked for obstruction. The con- densate pump assembly can be re- moved through the side access panel. After removal, inspect the drain pan to determine if the condensate is not being removed properly from the unit. Inspect all drain lines to ensure there is no blockage preventing condensate removal.

Q:How long will the fan run?

A:While the unit is in cooling or heating and auto fan mode is selected, the fan will cycle with the call for cooling or heating. When the room tempera- ture reaches setpoint temperature the heat/cool call is dropped. The fan will then stay on for an additional 60 sec. to purge unit of any residual energy.

Q:What causes my indoor unit to freeze-up?

A:Evaporator freeze up is usually the symptom of another problem. CAC air handler units are equipped with freeze protection to prevent freeze up from occurring. If freeze up does occur then check the following.

•Check that the freeze sensor inserted fully and snug in the coil ﬁn. If not an- other location may need to be select- ed. Be careful not to insert the sensor directly into the coil tube rather insert the sensor between two tubes.

•Check the indoor air ﬁlter. It should be clean and free of dirt. A dirty ﬁlter will reduce airﬂow and efﬁciency. Also check that the coil is clean. If the coil is dirty then it should be cleaned us- ing an appropriate coil cleaner or mild detergent.

CAC Cassette Evaporator

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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.