COMPONENTS TESTING (Continued)

FAN MOTOR

A single phase permanent split capacitor motor is used to drive the evaporator blower and condenser fan. A self-resetting overload is located inside the motor to protect against high temperature and high amperage conditions.

WARNING

ELECTRIC SHOCK HAZARD

Disconnect power to the unit before servicing. Failure to follow this warning could result in serious injury or death.

BLOWER/FAN MOTOR - TEST

1.Determine that capacitor is serviceable.

2.Disconnect fan motor wires from fan speed switch or system switch.

3.Apply “live” test cord probes on black wire and common terminal of capacitor. Motor should run at high speed.

4.Apply “live” test cord probes on red wire and common terminal of capacitor. Motor should run at low speed.

5.Apply “live” test cord probes on each of the remaining wires from the speed switch or system switch to test intermediate speeds. If the control is in the “MoneySaver” mode and the thermostat calls for cooling, the fan will start - then stop after approximately 2 minutes; then the fan and compressor will start together approximately 2 minutes later.

Figure 23

Blower/Fan Motor

CAPACITORS

WARNING

ELECTRIC SHOCK HAZARD

Turn off electric power before servicing. Discharge capacitor with a 20,000 Ohm 2 Watt resistor before handling.

Failure to do so may result in personal injury, or death.

Many motor capacitors are internally fused. Shorting the terminals will blow the fuse, ruining the capacitor. A 20,000 ohm 2 watt resistor can be used to discharge capacitors safely. Remove wires from capacitor and place resistor across terminals. When checking a dual capacitor with a capacitor analyzer or ohmmeter, both sides must be tested.

Capacitor Check with Capacitor Analyzer

The capacitor analyzer will show whether the capacitor is “open” or “shorted.” It will tell whether the capacitor is within its micro farads rating and it will show whether the capacitor is operating at the proper power-factor percentage. The instrument will automatically discharge the capacitor when the test switch is released.

Capacitor Connections

The starting winding of a motor can be damaged by a shorted and grounded running capacitor. This damage usually can be avoided by proper connection of the running capacitor terminals.

From the supply line on a typical 230 volt circuit, a 115 volt potential exists from the “R” terminal to ground through a possible short in the capacitor. However, from the “S” or start terminal, a much higher potential, possibly as high as 400 volts, exists because of the counter EMF generated in the start winding. Therefore, the possibility of capacitor failure is much greater when the identified terminal is connected to the “S” or start terminal. The identified terminal should always be connected to the supply line, or “R” terminal, never to the “S” terminal.

When connected properly, a shorted or grounded running capacitor will result in a direct short to ground from the “R” terminal and will blow the line fuse. The motor protector will protect the main winding from excessive temperature.

Dual Rated Run Capacitor Hook-up

15

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Friedrich R-410A service manual Capacitors, Capacitor Check with Capacitor Analyzer, Capacitor Connections, FAN Motor
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R-410A specifications

Friedrich R-410A is an advanced refrigerant widely used in HVAC (Heating, Ventilation, and Air Conditioning) systems, known for its high efficiency and environmental friendliness. As a hydrofluorocarbon (HFC) blend, R-410A has become the preferred alternative to R-22, which is being phased out due to its ozone-depleting potential. One of the main features of R-410A is its high latent heat of vaporization, which allows for efficient heat transfer and improved cooling performance in air conditioning units.

Technologically, R-410A operates at higher pressures than older refrigerants, meaning systems designed for R-410A need to be built with more robust components to safely handle these pressures. This results in a more compact system design that offers enhanced performance and reliability. The dual-component nature of R-410A—composed of difluoromethane (R-32) and pentafluoroethane (R-125)—provides an optimal balance of thermodynamic properties, leading to superior energy efficiency, especially in variable speed applications.

In terms of characteristics, R-410A has a higher cooling capacity, which enables HVAC systems to effectively cool larger spaces or run more efficiently when cooling smaller areas. The refrigerant is non-toxic and non-flammable, which enhances safety during its use. In addition, R-410A has a lower global warming potential relative to other refrigerants, making it a more environmentally responsible choice for modern cooling systems.

Moreover, R-410A systems typically require less refrigerant charge due to their efficiency, contributing to reduced greenhouse gas emissions. The adoption of R-410A aligns with regulatory trends aimed at minimizing the environmental impact of refrigerants in cooling applications.

Overall, the Friedrich R-410A refrigerant embodies a combination of technology and environmental stewardship, making it a cornerstone of contemporary HVAC design. Its ability to provide effective and energy-efficient cooling solutions while being compliant with modern environmental regulations positions R-410A as the refrigerant of choice for engineers and installers focused on sustainability and performance in air conditioning systems.
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